It's great to see that Yahoo! has listed pool as it's #1 pool game out of the top 20 games on their site. It looks like they have cash games as well as
free games which. The cash pool games from Yahoo! appear to be run by King.com. King.com and Yahoo! will have some sort of sharing arrangement in the background so this is not always the best game to be playing at. It can sometimes mean that there are not as many prizes coming back to the player themselves as each of the sites want to take their cut.
Personally I think there is just too much advertising on the Yahoo! pool game site but some players don't mind this much advertising to be able to get to a free game. I find it is distracting for the play of the game itself.
It's your choice but at the least it is great to see Yahoo! games being promoted well on their homepage. The more promotion the more people playing!
Good luck for your next game if you're playing on Yahoo!