Twitter has gone on a charm offensive, after buying Tweetie and announcing it's going to make its own URL shortener and users won't get the choice about whether or not to use it. We are still nice guys, they're saying, and you'll still be able to work with us.

I'm sure they mean it. Equally I'm sure they shouldn't be issuing reassurances in this way.

Let's drill down a little and ask who or what Twitter is for. The users? No. The developers? No. It needs the first of those groups, certainly, but like all private businesses it's actually there for the shareholders. It's like a dirty little secret the IT industry has - it's not for us, it's for the people who own it.

And Twitter is at a very vulnerable stage from its shareholders' points of view. It's announced sponsored Tweets but there isn't yet any evidence that they'll work - there couldn't be, before they're in use.

But the company's going to have to do whatever it takes to justify its existence by turning a profit, and it's going to have to do it soon. Reassuring anyone, developer, user, whoever, that the status quo is safe, is badly timed.