Beware of this company (RivetGames). They are not a free site. It used to be and people were led to believe they would be grandfathered in--now it has become pay-only and many people will be locked out of their accounts on 4/26/11.
For the past year, they have repeatedly changed the rules of the games, jerking people around and upsetting most of the players, many who have been loyal players from the beginning.
The cleverly worded TOS allows them to do as they will, but most companies show more respect, appreciation and fair play to their customers. The site is full of glitches and the new owners don't seem to have a clue what makes sense. The announcement of the pay-only came a few days ago and as of right now there are over 4,000 posts complaining of this in a 267 page forum thread.
Joining this site will result in disappointment and frustration.