I think the newness about this is that they've released the code on github under MIT, so you can self-host the service if you want. I think none of the othe rprojects mentioned here have are opensource or have a slef-hosted version.
According to http://www.wtfpl.net/about/, the first rule (and the only rule) of WTFPL is:
0. You just DO WHAT THE FUCK YOU WANT TO.
So, I guess you can self host it (: