I was quite happy with Yahoo Games when I was a Windows user. I played Chess, Hearts, Euchre, and more on Yahoo Games. Once I had any problems with Java applets, however, Yahoo Games became a casualty of those problems. I literally spent at least an hour a day on Yahoo Games before switching to Linux. At that point, Yahoo's technology got in the way and I looked for non-Java alternatives. Unless you have no chance of having non-Java competition (I'm thinking of my local gas company here), it would really be a shame to lose potential users because of your technology choice.