When people you don't know on Twitter follow you, do you return the favor?

I’m pretty much of a twit when it comes to Twitter. What are the reasons to follow someone, or to not follow them? What does flowing someone change in User Experience. Aside from the usual rules of civil discourse that apply to all conversations, are there any parochial protocols in the Twitterscape that I should be aware of?

What’s the best that I can hope for by using Twitter, and what are the pitfalls to avoid? Just so you’ll know, I have absolutely zero interest in using Twitter as a vehicle to tell everyone what I am doing moment by moment as I move through my day, hand-held device at the ready to announce “I’m on the T coming in to Haymarket Station.” I mean I do get the notion of “Who cares?” so I will not be that particular sort of twit.