Don't they get a few million users? I'd say it's definitely nothing to scoff at.
It makes me wonder how many big profile websites might look like this or worse.
I still remember a week into the first job fresh-from-college me marching into the VPs office to tell him the source code was terrible and they were only still running due to luck. It was not well received (or right)
Things are different today though,people tend to use native apps, users want realtime features,hard to do that in pure PHP and scale.You often need 3rd party techs,mostly java based...
As if OpenSSL didn't prove this already.