I found this piece of information on the net. I think you'll find it enlightening.

"What this means, is that given current JDate rules that only allow paying members to reply to messages, if you buy a membership on JDate, only 3.5% of the people you send messages to will be able to reply or acknowledge your message in any way. See, JDate gives you no indication whether or not a profile you are interested in belongs to a paying member capable of replying. That kind of sucks. Imagine sending out 100 messages to 100 “active” members and only 3 (and a half) of them are capable of replying, let alone willing to reply!"