[dpeq]

That's an interesting angle and I always thought, why is there a search.twitter.com and not just a little input at the top every page on twitter.com.

[patio11]

I suspect that that design decision is failwhale repellent. The only problem with a search box on every page is that people would probably use it.

[rdrimmie]

IIRC, twitter not too long ago acquired a 3rd party company who offered better searching. It may be an integration issue as well.