I heard that if I buy the game in the store, I still have to go online and do something and download files to even play the game. So I have a few questions about this.

1) Is it true?
2) What exactly is the deal with it and what is it?
3) Can I put these "files" onto a disc so I never have to go online and deal with this bull if it exists?

I just have these questions because no one seems to be talking about it a lot and to me this is a huge deal. If I want to play the game in 20 years from now on my new rig at the time and Valve is dead then I guess I would be ed at the time. *is always thinking ahead*