Trend Search:

This will help you see what discussions are current, and how interest in specific topics changes over time.

(Hint: separate different terms with commas.)

Influence Search:

Search all of Twitter, but sort the results by the people who get retweeted the most. This will help you find opinions that others feel are worth spreading.

Conversation Search:

Find related conversations that are happening now. Get into the conversation and make friends!

(Hint: Put a -keyword in the search to skip results with that word.)