I dated a girl for three months from OKC, so I can't say that it doesn't work. In general, I would say that 25% of the women I send a message to will respond. Of that, probably another 10% make it to a date.
Like any type of dating, it takes work. You need to read the entire profile, see what you like or don't like. Then send a message based on his/her profile with something clever added. I pretend that dating a game, that way I don't get hung up on whether someone responds to me or not.
Don't be negative in your profile, or your messages, whatsoever. Put four or five photos of just you on your profile, look happy. "Hi, hello, hey there" is not message. You need to read the entire profile and put some substance into a message. It takes practice, not everyone will respond.
My pet peeve is where someone responds with a dead end message, so it becomes my responsibility to keep the conversation going. If it goes on like that for more than a week, I stop messaging.