As someone who used to develop in ASP.Net and still maintains a lot of ASP.Net code, it's nice to see some progress being made. Clean URLs are certainly a good thing.
Meta keywords aren't used for search engine rankings anymore, but that doesn't mean they aren't useful. The page you linked to mentions that they are used for the Google Search Appliance (for example). Also, they're still good for categorizing content, bookmark tagging, etc.
Not really SEO, more good practices for implementing web sites with sensible and readable URLs. Good to catch up with the open source world, I suppose.