The author doesn't seem to know about http://pump.io/ which is the successor to StatusNet (now GNU Social).

Evan's doing good work, and it's already used by several interesting personalities (joeyh from Debian/git-annex fame, Bradley Kuhn who's fighting the good GPL fight, and many others).

It's easy to try... there's already many many hosts and you can try one at: http://pump.io/tryit

f-droid.org is an alternative to Google Play that's full of open source Android software, pre-built from the source. It's like the debian of the Android world.

I use it on all of my devices, both those with Google Play and those without.

It took years to get well-validated HTML & CSS... though I hope things have improved, I wouldn't expect improvements until it's beyond embarrassingly late.

Missed the sub-100's by a bit, myself. It took me a while to realize that logins were possible (or useful). At the time, the comments weren't even close to the most interesting part of the site.