Treat it like any intertubes site... it isn't secure. That said, the information they have isn't all that exciting in the grand scheme of things. You could file the information there as "mildly important". They can't steal your money, but if they managed to hack the site and take all the user profiles, they would have a good start for rocking some identity theft, which while annoying, isn't generally the end of the world. Social security numbers, names, and addresses are a dime a dozen and not all that valuable.
Whenever you hand over your password, you should just assume that it is going to be stolen along with your e-mail address and user name... which is why you should never use the same password twice, especially for important things. For truly important things, you should be using two step encryption.