Yes, yes, I know, the supposed point of the website is to "warn" other people about these individuals and their bad behavior. And some people, indeed, seem like they ought to come with a warning label tattooed on their faces. But if what they've done isn't considered illegal or a threat to someone else, but just hurtful and/or stupid, don't air it to the world. Remember that Golden Rule you heard at some point while growing up? This is a good time to follow it.
Some people do stupid things. Some people do stupid things with abandon. Some people do stupid things and regret them. Some people don't do stupid things, but have bitter, shallow exes who enjoy ruining other people's lives by making up falsehoods about them. And I can guarantee that all of these kinds of people are well-documented on that website.
Look, if you've been (or are currently) with one of the first two types of people on the above list, you have two choices: take it or leave it. Literally. Either put up with it or walk away from it, but whichever you choose, shut up about it. No one besides your mother, sister, or best friend is going to care about what he did anyway, and spouting off to the public at large only makes YOU look like the fool, not him. If you must vent, (and we all must from time to time), there's a time and a place for it, and that's in a private conversation with your therapist, mother, sister, or best friend.
If you've been (or are currently with) one of the latter two types of people on said list, you have no business dragging their name through the mud to begin with. If you publicly shred someone's character with falsehoods, you'd best expect the same fate yourself.
I don't really empathize with either party in this guy's lawsuit (they both seem childish and vengeful), but I do hope it brings about the end of such blast-your-ex forums as the one she posted on. It's bad enough when people take to facebook to rip someone apart, but at least that's (usually) limited to a select group of people, and not searchable on a major search engine. Just because the tabloids get away with defaming someone's character (and they don't always get away with it-they lose plenty of lawsuits themselves) doesn't mean you will. Even if what you write is true, it still makes you look petty for making it public, not to mention the revenge acts that might follow.
I know, politicians and Charlie Sheen tear people apart publicly all the time. But before you're tempted to follow their shining examples, remember what the majority of people think about them. And ask yourself if that's how you really want to be seen as well.