There had been beta testing and release candidates out prior, and there were pre-release versions to many students and subscribers to various things.

But the 22nd was the day it turned up on store shelves and pre-installed on computers. It’s also the day many software vendors targeted to ensure their products were compatible, etc.

So yes, it was the official launch date. Now you’ll start seeing it everywhere and in your local electronics store. New products you purchase will start indicating if they’re "Windows 7 compatible" etc.