Twitter is certainly an interesting phenomenon and seems to be
growing with an increase in non-teen users. I think with increased use of the Web using mobile devices we will see more of this. Tweets can be, among other things, conversations that are happening in the Cloud. You can follow or be followed as a part of the means of conversation. But you can also see what is happening out there in the global mind.
Monitter is one way you can see tweets based on search terms. Really interesting stuff. I look forward to see how these resources develop.