During sessions/workshops on MVC, I would say that 90%-95% of the attendees (yes I do "poll" the crowd, so it's based on facts), walk out liking MVC and realizing it's potential. However, there is one frequent question that I'm asked:
How do we know if Microsoft is going to continue to support ASP.NET MVC?
Personally I think that they will continue to support it, but I can't read the future (If I could, trust me, I wouldn't be blogging about it). However, yesterday's announcement changes things. Even, for the sake of argument, if Microsoft decide to discontinue MVC, who cares. They've made it Open Source. So tomorrow, any company (including your own) could pick it up and continue to support it. This should add extra guarantee for those in doubt of whether to invest or not into ASP.NET MVC.
On the other hand, if you're the kind of developer/shop that doesn't buy into Open Source, move right along, nothing to see here, business as usual. Or wait, maybe it's about time you realize that Open Source is not such a bad thing after all...
Congratulations Microsoft, Phil Haack & Co. Good move!