SH started out like any other startup, with the best of intentions and a cool idea but it just didn't take. The issue is that they're on the line to deliver and they haven't had the traction they'd like so I've seen it slide, slowly, over an extended period, into a desperate place that leaves them doing ugly things. You should read Rahul's blog on finding product fit, it tells you much.
Personally, I now think they're in a position where they are trying to mooch everything they can off of users in order to try and build a better product coupled with finding ways to be "unique" that will make them money/attractive. This means they end up in sketchy territory i.e. the pixels, forcing people to reveal how they use gmail in order to sign up, tracking every-single-aspect of how users are using their site, hyped up bullshit etc. I don't know if they're harvesting actual user data.
The fact is, they're between a rock and a hard place. They aren't profitable, and there's no real exit. Whatever features make them unique can be copied in months, if not weeks by any other provider. Why would Google buy them? Also, the feature set, as good as it is, only appeals to a tiny subset of users of email. Other aspects like corporate email not being allowed to be accessed by third party clients etc makes a difference too.
I wish them all well, but by God I would not want to be a part of this thing. It stinks.