Summize lets you search Twitter for the types of conversations you're looking for. Just type in a word and find all the Twitter posts with that word it.

For instance, I typed in 'autism' because I have an interest in finding other parents who have children with autism. There are, of course, a huge number of posts with the word 'autism' in them. Refining my search I typed in 'autism children' and received posts that where more what I was looking for.

This is a fun tool that you can use to browse through Twitter. Find other people who like the same things you like and add them to your Twitter friend list. Then you can be part of the conversation too.