C++ would be absolutely terrible for social media applications. There, the barrier isn't usually the speed but correctness and maintenance overhead.
If Ok-Cupid were started today I highly doubt they would do that the same way. But given when they did start it I figure they literally did not have a choice.
They've also open sourced their server: https://github.com/okws/okws
It's still got the same C warts that C++ does in a lot of place, but it is far simpler and less leaky than C++.
C++ is still faster and more cross platform, than objective-c
--Have done both professionallyThere's a reason why every single AAA studio uses C++ for their engines and titles. And that's the same reason why it is terrible for social media applications.
Then they put a sane, modern language on top of it many places, Actionscript at EA, Python at many other places, LUA at others, C# at others, and write in a high level language that doesn't leak abstractions like a nut milk bag.