How do you get your followers on tumblr to interact with you?

That’s probably because Tumblr isn’t a social network in the traditional interactive way. You post stuff, and other people see the stuff, but it’s set up to be much more like how you watch tv than how you play a board game. Even the most popular tumblr blogs don’t have much interaction, although often times the interaction happens somewhere else online.

Just use DISQUS to add comments to your tumblr. It is pretty easy to get working.