Navagon: Which would make perfect sense if game development teams developed retail websites and game clients. Or if it took a whole development team three years to add Mac support and achievements to games. You're just blindly guessing based on zero information here.
I never said they were programming the website, that's what web developers are for. For me it makes perfect sense to assume that a game developer would program the Steam client considering that the Steam overlay is part of the client and it has to integrate WITH games so they have to know how to do that without breaking said games. Also the same programmers that wrote the net code for Valve games could be programming VAC because they compliment each other. An lastly, I can't think of anything that makes more sense than asking the developers that programmed the Source engine to update it gradually and PORT IT to OS X and Linux. They also had to program Steamworks features such as cloud support, matchmaking, etc.
Of course this is all just conjecture, I am guessing that their old programmers have moved to tasks more in line with their current objectives (pushing Steam's dominance in the DD market) and you guess that they are doing nothing and collect their paychecks at the end of the month just for warming their chairs.