I suppose Twitter has its uses. But I've identified a personal problem with using it, which is of course that when I'm posting tweets, I'm not being productive elsewhere (including here). I once described Twitter as ADHD blogging, but I think it bears closer resemblance to an old-style telephone party line -- it's easy to get sucked into the chattering and lose all track of time.
Which reminds me: I'm sure someone else has already identified this particular metaphor, since I always seem to come late to the cognitive party, but I'm pretty sure the Internet is actually the modern realm of Faerie. Think about it. You have mortals who stray within its boundaries (often in the dead of night) who are never -- well, OK, rarely ever -- seen again in the light of day, and if they do appear, they're weak pale things who can't wait to get back to the magical domains they visit at night. There are enchanting and dangerous things to see and do, beings who often appear in strange fey forms, and a stretched sense of time where hours go by like minutes (has anyone written "Rip van WWWinkle" yet?). It is easy for the weak-minded to be ensorcelled by such a place.