If you visit Twitter.com today, you may notice a brand new home page (if you are not logged in). The home page really has a strong focus on search. Here it is:
Why? Twitter said to help "people access Twitter in more relevant and useful ways upon first introduction lowers the barrier to accessing the value Twitter has to offer and presents the service more consistently with how it has evolved."
This is an interesting move for Twitter, clearly showing the direction Twitter wants to move forward with.
Forum discussion at WebmasterWorld.