[Dutchess Eglantine]

I'd say they shut down because of a lack of things to do (games most likely)
For example;
The main bonus with gaia is that there are a lot of interesting games you can play that suck you right in and give you something to do if no one's answering your posts at that time. Also, it's a way to get fun little prizes as well.

However, regardless of how cute the avis, if someone is easily able to get bored then the likely hood that they'll return to the site diminishes.