As other people have written in this thread, what goes on there isn't all bad; if it were, craigslist would probably have a much poorer reputation. (I don't use the site for myself, but I help someone with the occasional posting, though for the type of thing that involves a semi-public event with multiple people at once and no large amounts of money changing hands.)
One key is being careful. Other people in this thread have mentioned safety tips. I haven't looked at every link yet, but safety is a good thing.