I completely agree with you, that the whole Twitter craze has changed a lot. I still love LJ and visit pretty much daily to read my flist, but I don't update as much anymore. Mainly because I don't like to read/write one or two line entries. So I usually update about once a week when I have more to say. Twitter is perfect for random thoughts and stuff as you said. I update that daily. It's also more convenient. I can get Twitter on my phone, where as LJ is not quite as handy that way. But I enjoy both, so I don't intend to switch to one or the other anytime soon. I haven't converted to Tumblr yet, though, and don't plan to.

But I think the whole Twitter communication thing is really fascinating. It's really a phenomenon. Pretty cool if you ask me.