My take on it is that it is indeed just a post-it note collection, and that they have had problems with both scaling and usability since the inception. i mean, we hardly ever see the Fail Whale any more, and that used to be a daily occurrence.

My impression is that it was launched as a sort of "this could be fun' project, that then got far more attention and use than expected, and has lurched along the road of notability ever since. I have no idea how they are paying for any of this, since there aren't any ads, there's no donation button, and their FAQ to How do you make money on this? just says We don't, yet.