[Twitter's new VP of Operations, Santosh Jayaram] told of being in the Twitter offices in San Francisco on March 30, when the Twitter engineers noticed that the word "earthquake" had suddenly started trending up. They didn't know where the earthquake was. Several seconds later, their building started to shake.
The earthquake had been in Morgan Hill, 60 miles south of San Francisco, and the tweets about the shaker reached the office faster than the seismic waves themselves.
Rafe Needleman writing in Cool changes coming to Twitter Search.
Those cool changes include indexing the content behind links that are tweeted and ranking search results according to a reputation ranking.
Stating the obvious: Once Twitter has nailed search they're halfway to monetizing their business model -- and seriously competing with engines like Google. Twitter has an advantage that Google doesn't have: homophilious network neighbors, which research has shown to be a powerful conduit for influencing others and for identifying affinities that don't materialize via traditional demographic profiling.
With the introduction of more powerful and reliable search capabilities Twitter could become a serious contender to Google in the search space.
 Worth noting that Google has attempted to accomplish something along the same lines by introducing the ability to tether an individual profile with search history (even more so now that they've introduced profile pages) and by letting folks score and record the importance of their search results.