First result for the google search 'Twitter' isn't Twitter.com (google.com)

That's pretty interesting - I guess search.twitter.com is getting links at a better exponential rate, and that matters to google a lot. Thanks, while this could be a one-off thing, it's worth investigating for its implications to SEO.

My first result for 'twitter' is indeed twitter.com.

Uh, yes it is? At least for me.

You're link is broken. There's a "q=twitter#sclient=psy..." and "q=twitter" in that URL. Did you break it on purpose? Or did Google mess up? If you remove the "q=twitter#" it works fine.

it is for me.