I was also very cynical until I tried it. But:
Some people can actually be entertaining in 140 characters (but not many) eg: @jimmycarr @madeupstats
Others are great sources of links you wouldn’t otherwise see eg:
@glinner (Graham Linehan)
Some are about the news, or in the news eg: @tom_watson
Just surf it, search for your interests, look at plenty of profiles. It’s not really “personal” like facebook, so you can try out following people and then drop them if you don’t find them engaging. Odds are no-one will notice or care.
It’s good for dipping in & out of – keeps me supplied with entertaining randomness during my commute.
Also, if you’re active on linkedin or facebook, with some minor tweaking, it turns into a nice easy way of updating them on the fly.