I went through a phase where I was looking for hook ups, and I used an online adult dating site. The first guy I met actually went really well. But later I found out he was married and was hiding his activities from his wife. I felt really guilty about that for a while, even though we'd already stopped seeing each other. The couple guys I met after that were just kind of weird, and one of them really wanted to rush into being "a couple" and had me meet his family and was talking about moving in together. I had really just wanted a quick hook-up, so that ended kind of badly.
So overall I regretted getting involved with that site and deleted my account. It's not something I would do again, it's just not for me.