I wish there was some granularity to "online." I met my wife on a BBS in 94. It wasn't a dating site, it was a discussion board, and neither of us was looking to hook up with anyone. There are lots of things like that, but I'm guessing dating apps/sites are the biggest component.
I wasn't meaning to say that my situation itself was representative, just that most people see that line and think dating sites, and that's probably not completely correct. There are lots of online venues, like games, that aren't dating sites, but I didn't know what the breakdown is.