Looks like app.net isn't perfect either. Their HSTS isn't implemented correctly. Only 'alpha.app.net' and 'join.app.net' are protected while 'app.net' is not. They fell into one of the common pitfalls with their http->https redirects: http://coderrr.wordpress.com/2010/12/27/canonical-redirect-p...
You can verify this at: chrome://net-internals/#hsts
My understanding is app.net is trying to be a paid version of twitter. There was/is much debate whether it could ever take off. This is the first time I've ever seen someone link to it. Although now I realize that the link is to the app.net cofounder so that doesn't really say much.