I still (often) have doubts about whether Twitter is a valuable medium, but I see, looking at my archive, that I've now been tweeting for nearly seven years. Gosh. So it is at least a long-lasting one.

I'm far from a heavy user, though: over that period I've only averaged 1.3 tweets a day, with an average length of about 89 characters. Mind you, that's still well over 40,000 words...