What are you doing?

Lead architect Blaine Cook and VP of engineering Lee Mighdoll have left Twitter, writes Silicon Alley Insider. In Cook's case the parting was reportedly amicable; Mighdoll was hired just three months ago.

The departures may serve as opportunities for Twitter to add a "scalability guru" to its ranks, which may help realize its potential as a real-time content publishing resource.

As ZDNet put it:

Twitter is at an interesting point in its development. The service is indispensable to some. Twitter has critical mass. Twitter could monetize that critical mass. But first Twitter needs to excel at basic blocking and tackling.

The site has trouble maintaining a steady uptime, especially during high instances of use (arguably, when it is most valuable), such as at industry conferences like SXSW or ad:tech, where many users either report observations at high speed or cover panels, sometimes word for word, for their readers.

And while it has to some degree brought SMS communication back in vogue, high phone bills have become an issue for users deluged by superfluous text-messaged "tweets."

Twitter has also failed to monetize its model.

This week the company hired John Kalucki, former co-founder of SQLstream; and Steve Jenson, who helped scale Blogger and Blogspot for Google.