The MLB rules committee has voted to make collisions at home plate illegal. This isn't an official rule change yet, as the decision still has to be approved by the players, but it sure looks like the home plate collision's place in baseball is no more.
This is a rule change that's been in the making for a few years now, due in large part to the fact that Buster Posey missed a huge chunk of the 2011 season after getting his leg broken in a collision with Scott Cousins. The new rule hasn't been formally drafted, but it will likely make it illegal for catchers to block the plate, and require runners to slide when coming into home.
It will be interesting to see how MLB eventually decides to enforce the rule. Fines aren't likely to curtail catchers from blocking the plate or runners from hurtling into those catchers, but in-game penalties such as an out or a run might do the trick. One of the former would likely keep catchers out of the way—what's the point of blocking the plate if it's automatically going to cost your team a run?—and that's the most important part of making this rule effective.
A lot of people are going to be complaining about how this new rule will just "sissify" baseball, but any rule that helps eliminate catastrophic injuries like the one that robbed Posey of nearly a full season is a good one. Besides, most catchers will probably be relieved to now have a good excuse to get the hell out of the way. Well, maybe all of them except Brian McCann.