I enjoyed the "travel log" aspect of it. It was fun to be able to look back a couple months and remember every restaurant I ate at, and every place I went.
The mayorships and badges were fun at first, too.
Ultimately, though, I decided it wasn't providing enough value for the effort I was putting into it, and stopped cold turkey.
They don't provide anything but I was responding to someone who asked what the wow facto was. There really isn't any wow factor, but for some reason people are suckers for achievements. Just look at pretty much any video game today for additional examples.