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I'd just like to add that a search for "git hosting" on DDG ("duckgoing" if you will) yields, aside from the SO quick info box (which mentions Gitorious and Redmine), unfuddle.com is the first result, github doesn't show up until the fourth of fifth, and I haven't scrolled down to look for Gitorious. It does, however, show http://git-scm.com/tools as the second result, which includes a summary of the most popular hosters divided by categories.

I get github as the second.

you can also add &pws=0 to the url

I'm sure the fact that you work for Gitorious' parent company has nothing to do with it ;-)

I wonder if Google actually knows that, or if it's something else that causes it.

For me Github is the third hit and Gitorious is not even on the first page.

I'm unfamiliar with Google's indexing algorithm, but it's also possible that the rank of the top pages has shuffled between when Linus googled it and now.