Well there is Chronicle of the Horse, but it doesn't really fit into your "friendly" category. It is active and has a lot of information but definitely tread VERY carefully or you may find yourself in a full out flame-fest! I usually skim it for useful info and rarely make a comment, there's just so much negativity, and I usually find myself put into a bad mood afterward. Anyway, it is something you could check out and I hope you can find other forums!! Good luck!