Well I was mainly referring to the idea of getting dates in general (merely getting your foot through the door, as it were). Having a successful relationship come out of it is a different matter (which, no I don't know anyone in real life who has had one from somone they met online).
Myself and 3 other of my friends met our SOs on Cupid - 1 of them is married and the other is engaged. I found it pretty easy to get my foot through the door, all things considered since I'm not terribly attractive and I'm unabashedly nerdy... getting a second date out of the deal, MUCH harder though. And going all the way to a relationship... I say I went on close to 100 dates before I found one.
My mom works at a dress store and she says that a lot of the customers met their husbands online, too.
Tinder is a bit after my dating time so I don't know how that works. And although I was able to meet a few girls in person it never really went anywhere... at least online you can 'vet' the person a bit, find out their age/interests/job/etc (the last girl I went out with that I met in person I later found out she wasn't even 21 yet. Sure I like my Vita but that's just WAY too young for me)
I'd imagine the ideal way to meet a girl for a lot of people would be through mutual friends. Unfortunately, the last time that happened for me it ended in disaster (I talked about it much earlier in this very thread
).
And finally, things are probably a lot different depending on where in the country you are. Where I live, most 20-somethings live at home due to a ridiculous cost of living, which hinders dating, and a lot of professional/educated women moved off the island or into the city.