You know all of the primitive, annoying things people do when they first join Twitter, like tweeting two words of an incomplete sentence, or posting the single most monosyllabic expression of the thing they are doing at the moment (i.e., "lunch")? That's exactly what the very beginning of Twitter looks like for its creators, too. And for fundamentally the same reasons: They didn't know how to use this thing. No one knew how to use this thing. It was brand new. It was twttr. (And at the time, it automatically tweeted from new accounts, "Just setting up my twttr.")
Though as you move through those early tweets you can see them start to figure out what this thing could be, slowly moving from something like a semi-private messageboard to something more closely resembling the way people use it today, at least between friends. Dom Sagolla is perhaps the first to really nail it: "oh this is going to be addictive."