Rated 2 out of 5 stars

Minuses:
1. It doesn't work for me: I'm using latest Nightly and I visited my gmail account and it didn't turn into an app tab). Same happens with facebook.
2. Dictatorship is bad, you need to add some settings and let users create their own rules to make this extension work for the sites specified by user.

Plusses:
1. The whole idea of your extension is good.

What Version

When you say nightly do you mean 10.0.2. That is what I am using and it works for me. I have not really fully tested it with facebook or twitter so that might be somewhat of a problem. Thanks for the review though.