Well it's sorta a virtual pet, sorta. Like neopets sorta.
This place existed before neopets, so many years ago. They were at another url and their interface was super slow and a bit annoying because of the slowness. I played this game for quite sometime (like 8 years ago heh) but lost interest over time due to the slowness of the site (and my connection at the time).
Recently I came upon them again and they sure have changed. The site is smooth and beautifully made, its fast and had a name change (I can't seem to recall the old name).
Basically it's raising a virtual horse to participate in competitions and whatnot. Now it used to be free, and from what I can tell it is still free for the most part. It seems you have to pay for special items and whatnot, but it looks like nothing else requires pay. It doesn't look like you are required to have the special items to enjoy the site so.. no biggie there. It looks cooler then I remember it being. I just started playing, it looks addictive so I'm afraid of spending too much time there (lol).
But I wanted to pass it along in case anyone else was interested http://www.howrse.com/