I think that datingsite are really populair because there are far more singles than ten years ago!
this is an evergreen industry. the challenge is differentiating yourself and providing a twist to the age old concept that everyone is so used to. tweak the wheel, dont recreate it!
Dating or match making is a segment that is still popular and it is going to retain its popularity. So this business is definitely a lucrative one. Likewise in the adult entertainment industry escort service is quite popular and high profile professionals like Milan call girls are in great demand.