Speaking for myself and probably most other horse people, the hardest thing to think about are abused, neglected or unwanted horses. Reading John's article made me cry (not helpful), want to adopt another horse (not financially possible) and spoil the one I have even more (will start tomorrow). Obviously, this problem is a big one and not going to be solved overnight. But I think a small difference can be made if each person can take a few hours out of their month, a few dollars from their savings, or use their contacts to help place even one horse.
I know this has been said before in a million different ways, but please read the article (though Im guessing most of you have already) http://eventingnation.com/home/ and see if there is anything you can do if you aren't already. It amazes me everyday how special these animals are and how much they put their trust in us. So earn it. Even if you can't do a whole lot, a lot of little things add up.