[bane]

It seems to be an engagement issue. Populations that don't message or participate or show interest should be encouraged to in some way - like "your profile will only be viewable for x number of days unless you start messaging other people"

[Kalium]

Unengaged users are an immensely valuable asset. Show a guy that there are three thousand women in his city, and he'll be very interested. Show him that only three of them have logged in in the past week, and he'll be a lot less interested.