After measuring activity across the 80,000 or so sites in its ad network, Chitika reports that Bing usage is tied to which version of Internet Explorer a person uses. Specifically, Bing usage increases as users upgrade to newer versions of Internet Explorer.

As you can see, Bing usage jumps from 16.9% among IE8 users to 22.9% among IE9 users — that’s a 35% gain.

Is this just a case of IE9 making Bing the user’s default search engine? No, not really. A Microsoft spokesperson says users who upgrade from one version of IE to IE9 will maintain the same preferred search provider they chose previously:

If a user has selected another search provider as the default (via the IE Gallery) in a previous version, that preference will be preserved when upgrading to IE9. Bing is the default on new IE9 installs.

So, it sounds like the explanation for Bing’s popularity among IE9 users is either A) A lot of people are switching from another browser to IE9 and using Bing by default, or B) a lot of IE9 users are upgrading and switching to Bing at the same time.

Google, of course, remains the number one search engine among all IE users. But it’s interesting to note that Google does see a drop-off in usage between IE8 and IE9, corresponding to some degree with Bing’s increase in usage between IE8 and IE9.

And then there’s Yahoo. According to activity across Chitika’s network, Yahoo users are generally web browser luddites. Ouch.

Postscript: I should also mention the possible impact on browser/search engine use from deals and partnerships that have been struck over the years between the major search engines and various computer makers. Here are a few of our past stories covering that topic:

• Deal Puts Microsoft Live Search On Dell Computers, Verizon Phones — Will It Help?
• CES: Microsoft Expands Scope Of HP Search Relationship To 42 Countries
• Bartz: Yahoo’s Search Decline Due To Dead Toolbar Deals

Jeremy has the side-by-side photos of how the pages looked. Google’s page has since changed. In many places, the copy was either identical or the word Yahoo was simply swapped for Google.

At best, I thought perhaps Google was using some type of template page that Microsoft was encouraging cobranded partners to use. Jeremy says that’s not the case.

Google’s Matt Cutts weighs in with his own post on the topic, damage control by pointing out how Yahoo has copied Google’s ad style, Yahoo ads evolving to match what Google’s showing currently.

True. And Yahoo can easily point out that Google decided that paid ads made sense after imitating GoTo (which Yahoo later bought), plus that Google got real success with ads by moving to a CPC cost format rather than the CPM that they started with.

If I had time and desire, I’d sit here all day pointing out similar things that Google has copied from others, that Yahoo has copied from others, that Microsoft has copied from others, that Ask has copied from others. There’s no end of finger pointing that can be done.

I will say that I find a difference between mimicking user interfaces and simply flat-out copying a landing page. If a particular user interface or standard has evolved into a standard, I can generally back the idea that the industry moves to that, regardless of who pioneered it. But just taking a page and doing a search-and-replace? I cut less slack on that.

There’s no end of discussion sparked by the pages. To get a good roundup, see here on Techmeme for those talking about Jeremy’s story and here for those discussing Matt’s.