We had to solve scaling issues most of the time. VZ was running on a multi-tier platform with services written in Java, PHP, Erlang, C++ and Python. 17 million users with around 25 billion requests per month (without static content)...
Some numbers from 2010:
- 60.000 req/s (without static content)
- 2.5 mio. memcache ops/s
- 300k queries to the database tier
We've built that platform with a team of around 20-30 engineers and we had to solve the scaling stuff first - before we could add new features to the platform.
Today it's easy to store 3 billion files (photos). You could easily use S3, but 2007 these services didn't exist or most of the cloud services just started with their services.