I've got a Tumblr! Well, several, actually. My pony one is
The New Gray Mare and my personal/main is
Mari Lwyd. If I follow you, it will show up as Mari Lwyd.
Speaking of Tumblr, I should really get a que made for that pony one again!
Edit to add: If there's a particular Tumblr you want to follow, but don't like everything they post, you can install Tumblr Savior as an add on to your browser. That way, I can follow pony blogs and block all the Monster High/ Pokemon stuff I'm not interested in. It works off tags, so if the blog doesn't tag a post, your out of luck on it being blocked; but, for the most part, it's a pretty awesome tool that I love.