I guess I can't say that I'm surprised by the numbers released by Hitwise on the traffic connection between Google and Wikipedia.  You can't do many searches at Google that don't include at least one high-ranking link to some page at Wikipedia.  The user-generated encyclopedia recently broke into the top 10 online properties based on unique users.

The data released by Hitwise shows that Google is, at least in part, responsible for a lot of Wikipedia's recent growth.  In fact, only Google's own image search and MySpace got more traffic from the search giant last week.  When you compare that traffic to last year, Hitwise says it's an increase of 166%.  Wikipedia receives 70% of it's traffic from search engines and, not surprisingly, Hitwise says 50% of that search traffic comes from Google.

Depending on your opinion of Wikipedia, this news could come across in a variety of ways.  Personally, it disturbs me just a bit.  Based on the way Google says its search algorithm works, Wikipedia's loft position in the SERPs would suggest that Wikipedia has a lot of incoming links from "trusted" sources.   I have two questions:

1. Do "trusted" sources really trust Wikipedia?
2. If only 30% of Wikipedia's traffic is coming from non-search related means, where are all of these links that boost its ranking?

You'd think a site with a PageRank of 8 and enough incoming links to make it the "Google SERP pet" would get more than 30% of its traffic from non-search sources.  And keep in mind that that 30% is divided among several sources of traffic (like direct URL entry)… not just linkage.  But I digress.

Regardless of your opinion on Wikipedia, this information goes to show the potential of Google as a traffic generator.