You can get your regkey from your My Account page.
No, this isn't a new thing. It's been there for years. That's why it's undeniably the best deal in music software. Cubase, Pro Tools, Reason, etc. all cost money ($200-300 per version) to upgrade. ("best deal" meaning most content for your buck)
Awesome, thanks for telling me about this. Now I have the FL 10 fruity edition on my new laptop and I didn't even have to buy it. I'm probably more excited about this than I should be, but I guess it doesn't really matter.