I'm guessing that the majority of EFers are mid career, while the 10% you mention are still at uni/too busy partying to spend much time on EF.
What about sports or treading the boards as a way to meet people? There's a couple of expat sporting groups around, as well as English-speaking acting groups around Basel.
It will be slower going though. When I came over as a 26 year old a few years ago, meeting peers was hard as most expats are in late 20s++ (which as we know is just sooooo old ).
Whats up? I just got to Basel from the US about two weeks ago after graduating college. Everyone at my work speaks English and have offered to take me places but have yet to find many people my age around town, that speak english, to hit the bars/clubs with...let me know if you find anything.. (and yes, members, i will keep my eye on the 'social' calendar)
It takes time but you'll find some people little by little. In the mean time, go meet some of the girls who are over 25 & maybe go hang around places near the university.
i found one person! haha we met up a couple of days ago and it went well. hahah and i have volunteered at the ISB school for some event so maybe there will b mothers with daughters and sons! haha anyway im still looking,
couchsurfers, sports stuff all of it. think im gonna start kickboxing in Aschwill.
anyway thats what im doing so anyone else in my position theres a few ideas