ergophobe - 3:04 am on Jan 31, 2012 (gmt 0)
Sorry, I don't know Dolphin.
I think most mature CMS out there can handle that. Markus from Plenty of Fish always says, however, that it isn't about the features, it's about the efficiency. Dating sites have a lot of complex queries and huge overhead on each request. By their very nature, caching is hard.
So you can build a system that does everything you want, but getting it scale to the point that it makes money without all that money going to pay for servers is apparently the challenge.
So as I understand it, Plenty of Fish runs mostly on custom code in fairly low-level languages (C++).
So just as an example, your feature requirements would be easy to meet in Drupal, but if your community got big, you'd need some solid server power to keep it running I think.