With Spock, you can search on a person’s name or a keyword that may be associated with a person, and are returned a list of people with associated tags, photos, and web sites. From there, you can drill into more information about any of those aspects, add information of your own, or browse to people who are related in various ways.

Spock CEO Jaideep Singh says that their crawling and indexing infrastructure has the unique ability to identify people-specific data on web pages and extract only this information. Their algorithms combine natural language processing with machine learning and they augment this with human involvement—both community input and editorial oversight.

Tagging provides a unique twist on the search for people. As Singh points out, your search can turn into a discovery. You may initially search for information on Kristen Dunst, but then might follow the tags to see others associated with Bring It On and notice that several of those listed are also tagged with Buffy the Vampire Slayer, including Christophe Beck, who choreographed the music for both the awesome cheerleading movie and the kick ass TV show about the blonde girl with the pointy stick. Click “related people” for a list from another perspective.

In the case of Kristen Dunst, this gives you mostly a list of ex-boyfriends rather than costars. You view people in a larger context and can gain more insight with this type of system. You can also search directly over tags. For instance, a search for “Buffy fan” returns, well among other people, me. Singh says that only half of people-related searches are for names and the rest are topical, so having a way to categorize people into a variety of topics can be very useful.

Anyone can add a tag to anyone else. Spock is confident that the ability of the community to vote on tags will bring a Digg-like democracy to the results and will present an accurate picture of not only how people view themselves, but how the web views them as well. Singh notes, for instance, that while Google created an algorithm to keep George Bush from being returned as a top result for “miserable failure”, that’s a relevant result for Spock because it reflects the views of the community. (It’s currently the second tag listed for Bush.)

But tagging has not been without criticism. A Digg-like democracy can give power to the collective people or it can be a ripe environment for gaming, and in typical web fashion, that has already begun. Singh claims the malicious use of tagging has been extremely low and notes that anyone can request removal of a tag once they’ve claimed their profile. And then there’s Spock Power, which gives more or less weight to votes based on a person’s history (how often contributions have been voted up or down). They also point to their transparency. Since everyone can see how everyone else tags and votes, I know exactly who’s tagging me as a Buffy fan.

Spock is incorporating other community aspects as well. Once you’ve created an account and claimed your profile, you can add friends and mark people as favorites. It seems that Spock marks favorites for you as well based on matches it finds from your connections on social networks such as LinkedIn. You can also import your address books and start building up a full network of contacts. You can add information to each profile that only you can see, such as phone numbers and notes. With features like this, you can see a bit of Spock’s roots as the ultimate contact management system (after the founders become frustrated with the limitations of Outlook). Since Spock can be a combination of contact information you add about people and the information that Spock finds about them from the web, you can potentially do more useful searches over those contacts. Rather than just search by name, you can look for all your contacts who like to play golf or are experts in link building.

Creating an account and registering your profile not only enables you to take part in the community aspects of the site, but it allows you to engage in a bit of reputation management as well. Information that you add about yourself is weighted more heavily than information others add about you. Also, you can sign up for alerts about when others add information to your profile.

How relevant are the results? Spock is going after quality over comprehensiveness and are slowly expanding. They don’t include offline data, but are ambitiously aiming to crawl the entire web and extract all useful people-related information. They’re not there yet. Flickr photos are visibly missing, for instance, but they’re working on adding more data sources over time.

Singh acknowledges that extraction and aggregation are hard problems. They feel they have an advantage over Google regarding extraction because while Google is agnostic to the page type, Spock tries to identify pages and information specifically about people and then processes over that. Aggregation requires that you not only can classify the data as people-related, but can identify when data from disparate locations is about the same person. So far, Spock seems to be primarily concentrating on grouping profiles from social networks and adding links from blogs, news stories, and sites like Wikipedia.

They feel their “man plus machine” philosophy is a scalable and effective way to combine smart approaches to algorithmic classifications with crowdsourcing. While this multi-faced approach seems promising, they certainly have an uphill battle. Can they engage the community to add valuable information? Can they become comprehensive—both in the total number of people they profile and in the information about each person? Can they introduce a paradigm shift around where people search and how people manage their contacts that will trigger a move away from Google and Outlook for people-related data? And maybe most importantly, will all of these plays give them an edge over the other people search services in the space?

All of that remains to be seen, but certainly they’ll be expanding in these areas over time, so they’re well worth watching. Stay tuned in the coming weeks for the rundown on some of the other services and their approaches to winning the battle of the people search vertical.

Vanessa Fox is product team lead for Zillow.com. She was product manager for Google Webmaster Central before joining Zillow in mid-2007.

People search certainly isn’t new. As Michael Tanne, CEO of Wink, points out, in the days before mainstream transportation everyone knew everything about everyone else in a village. And if you didn’t know someone, all you had to do was ask around: low-tech but very effective people search. But the world got bigger and eventually came tools like white pages and public records. With the internet, this data was ported online and made more easily searchable. Internet communities that enabled people to create profiles populated with their interests added a whole new facet to people searching. The latest services take all of these elements and throw social networking, blogs, Wikipedia, Flickr, and the proverbial web 2.0 kitchen sink into the mix.

Talk to these companies, and you’ll hear terms like “semantic indexing”, “structured data”, and “social graph” tossed around. Nearly all of them attempt to provide some aggregation and organization to the plethora of social networks that exist every place you look and many employ social networking aspects of their own — from community tagging and voting to social connections and content generation. Looking at them, you might wonder if they bring order to the chaos or contribute to it. But they’ll tell you there’s a method to the madness, and their hope is to help you sort through the web and find everything you might want to know about any person out there.

You can also go straight to the social networking sites to search for people (even Twitter says it now does people search), but since those sites aren’t built to be search engines, it may be more difficult to find who you’re looking for, and of course, they will only return results for that single site. Facebook in particular has touted itself as a people search engine, but calling yourself such doesn’t make it so. Unlike many other social networking profiles, very little Facebook information is available to those not in the person’s network. At best, you can use a Facebook result to find friends you want to add to your network. It’s not ideal for mining data.

All this talk of Facebook opening up to search being a people search killer is so far just a lot of talk. In fact, their recent push to open up their data to search engines may benefit people search engines, who may now more easily add Facebook profiles to their data aggregation.

Todd Sawicki, who spent some time as VP of Marketing for Spock and is currently an advisor for Facebar, sees the people search landscape at a crossroads. “When people search companies started, the assumption was that they would help aggregate and distill the multiple identities people were creating online.  The goal was to create the complete view of you—likes, dislikes, background, friends, etc and since that information was spread around the net—aggregating that disparate information potentially provides a ton of value.

What none of the people search engines expected was Facebook.  In a social network like Facebook, users willingly handing over all the information that people search engines are trying to cull and aggregate.  Thus in a world where everyone is on Facebook, Facebook becomes the only place people need to go search for people.  Now, if everyone doesn’t flock to Facebook and other dominant profile-based networks emerge, then people search engines provide the important layer on top of those networks helping to connect the dots across them.”

While it’s true that Facebook apps enable users to aggregate much of their data from across the web (including blog posts, Twitters, and Flickr photos), only friends can view this data, which doesn’t make the results ideal for non-friendship searching. Facebook founder Mark Zuckerberg said as much in a recent Wired article: People already have their friends, acquaintances, and business connections.” “So rather than building new connections, what we are doing is just mapping them out.” This is far different from what some of the people search engines are attempting to do. Not all people searches are about connecting with friends.

What about privacy? Do these sites encroach on privacy by making information about people easier to find? For the most part, people search services are just providing aggregation for what you and others have put online. Google and other search engines have been doing this for years. If you’re concerned about privacy, you should check out the policies of any social networks you use to see what information is available to those you haven’t explicitly opted-in to your friends network. LinkedIn, for instance, makes everything public unless you choose otherwise.

In some cases, these services also enable the community to add information about you. Spock, for instance, allows the community to add tags that describe you to your profile. But someone could almost as easily create a web page about you that others could find through Google, so even that’s not new. All have policies around removing information if you request it. ZoomInfo notes that people often use their service to find out where on the web they’re being discussed and use it as a list of sites to contact. They then request removal from ZoomInfo last.

So, what of people search, old and new, should you try out? I’ll be going through them all in this series, but in general, the service that might benefit you most depends on the type of searching that you’re doing.

Connecting with friends. If you’re looking for friends (old or new) or for background on that person you just met at the bar, you can get dirt—er, information—using any of the people search engines out there. Anyone without a strong web presence may be difficult to find, particularly since consolidation can be problematic (Spock and Wink seem to be doing the most in this area). You may need to do double check your findings with a major search engine or search social networks directly. 

Genealogy. The newer people search services may not be all that helpful, since they rely primarily on web data and generally don’t include offline information. For historical information, you’re better off with some of the more traditional people search services or a genealogy service. However, these newer services might give you lots of eye-opening data about your current relatives.

Research. Each people search engine has a particular niche within the vertical and not all types of research are created equal. Want to find all the RSS feeds for someone? Wink may be your best bet. Want a golf partner in Seattle who’s also a venture capitalist interested in investing in a new widget company like yours? You might check out Spock. Looking for a VP of Marketing who’s worked in both the biotech and telecommunications industries in Miami? ZoomInfo may be the search engine for you.

Spock’s CEO Jaideep Singh points out his engine’s component of discovery. If you’re looking for information on Tony Hawk, you might use the categorical tagging system to get a list of other skateboarders, and from there find out about Shaun White and the entire 2006 U.S. Olympic snowboarding team.

One caveat: These services are at various stages of beta, comprehensiveness, and quality, so relying on just one at this point might lead to less-than-ideal results.

Reputation Management. If you care about managing your online reputation, you should check out how all of these sites represent you. Most of the newest ones rely entirely on crawling the web and anything they find is fair game. These sites can sometimes rank fairly well in the mainstream search engines, not to mention that they are used independently for searches. You should definitely claim and fill out your profiles.

Search engine optimization. Since profiles from these services can rank fairly well, you may as well beef up your profiles and add links to your blogs and any other sites you own that you want to drive traffic to. And since many of these services allow for keyword searches, potential customers just may find your business from your profile. It’s hard to tell how much traffic these sites will be able to generate, since the adoption is still in early stages, but making sure your information is up-to-date and accurate surely can’t hurt.

Job and industry search. If you’re looking for a job, to fill positions, or for information on particular industries or companies, searches using these services might produce data that would be difficult to find in the noisier search results you might get from a major search engine, which returns information for various contexts.

LinkedIn is likely the most well-known site of this type, but some of the other services augment a LinkedIn search in that they provide not only user-provided data, but also data found from crawling the web. You may still use LinkedIn (or these days, possibly Facebook) to make the connection, but you might do the initial research elsewhere. As Wink’s CEO explains, you can get a richer context for the person before you make the connection.

What’s next? Look for these services to become more comprehensive and improve in both aggregation and relevancy, at least in part by leveraging community involvement. New services are likely to pop up that have foundational elements of the semantic web or natural language processing, and that attempt to solve the problems of disconnected social networks. I’ll explore how the old and new school people search engines are doing in these areas in upcoming articles in this series.

Vanessa Fox is product team lead for Zillow.com. She was product manager for Google Webmaster Central before joining Zillow in mid-2007.