- Enabling the spell checker in the status message field, for catching those typos when hastily typing a message.
- Having the URL inclusion unchecked by default, while the shortening checked, since most posts do not include URLs (and it might be embarrassing if done inadvertently), but those that do usually want them short.
- Adding a character counter to help guard against the maximum message length imposed by some services (e.g. Twitter).
- Tightly placing the available services in a way that allows for an unambiguous selection.
- Using the Escape and Enter keys as shortcuts for canceling and sending the update respectively.
Posting is not the whole story, though. These services provide continuous streams of updates from friends that we need to monitor. Sifting through the updates in every service, while very useful, becomes tedious after a while. It is like making a mental note to check your e-mail every once in a while for new messages. It's one way to do it for sure, but mail notifiers have been around for ages and provide more of a "live" experience.
With the shape the world economy currently is in, you probably couldn't afford it, anyway.