So Sell Me on Tumblr

Tumblr: I have to admit, I completely don't get it, don't understand how to use it, and haven't been able to figure out the appeal, especially when there are so many other social media out there.

So, someone who gets it and likes it, please evangelize. I'd like to know what the big deal is.

If you don't like, don't get, or don't use Tumblr, please don't make the obligatory "I sneer at your Tumblr!"-type comment. I'm on an information-gathering expedition here, not looking for a geekfight.

-The Gneech

PS: I has one. Don't know what (if anything) I'm going to do with it. But I has one. http://the-gneech.tumblr.com/