Thats the new design strategy these days... Microsoft, of all companies, is actually trying to curtail that as much as possible with their open betas for major releases (re: Windows 7, MS Office 2010, Visual Studio 2010, etc.) and I think their products are totally seeing the advantages of this process.
Valve PRETENDS to have an open beta process, but in reality its just there to make sure their code doesn't crash. They don't do thorough testing and compatibility checks, its painfully obvious.