I dunno, some people get a bit weird fast. Remember, you're supposed to be putting your best foot forward so anything you see now will just be the tip of the iceberg. I do chat a little bit to screen out the obvious crazies, why bother dating them if they are obviously lying about their profile, have a temper, act looney or want things you don't (kids, religion, etc).
One problem with online dating is spending weeks/months chatting with a persona on the computer. Try to keep the dating pool to locals, and meet up sooner rather than later. It is harder to hide the "real person" in person than it is online, so that first date in a coffee shop or somewhere casual is the second screen.