Google’s Matt Cutts talks about multiple domains and 301 redirects in one of the recent videos uploaded to the Google Webmaster Central YouTube channel.
The question essentially asks if Google views the redirecting of many domains toward one domain as a sign of suspicious activity. Matt’s answer is that there are many companies — Google included — that own a lot of domains and have valid reasons to point them at the main domain. The additional domains might be typos or misspellings, or extra domains that are related to a company’s brand.
But he also says that 301s can be abused as a spam tactic, and that having a “ton” of domains redirecting to one domain might cause Google to take a look and see what’s going on.
Here’s the full, 90-second video below.