What exactly is Schema.org?
Why the uproar?
Who can benefit from it?
Who might be threatened and how could they respond?
What about Facebook? Probably the more interesting aspect of this story, what will Facebook do? Their interest graph combined with linked data has big potential, not only for semantic advertising. And Facebook is interested in getting as many of their hooks into websites as possible. Switching to Microdata and/or aligning their types with Schema.org's vocabulary could make sense. Webmasters would probably welcome such a consolidation step as well. On the other hand, Facebook is known for wanting to keep things under their own control, too, so the chance of them adopting Schema.org and Microdata is rather low. This could well turn into an RSS-dejavu with a small set of formats (OGP-RDFa, full RDFa, Schema.org-Microdata, full Microdata) fighting for publisher and developer attention.
I am glad that Microdata finally gets some deserved attention and that someone acknowledged the need for a format that is easy to write and to consume. Yes, we'll get another wave of "see, RDF is too complicated" discussions, but we should be used to them by now. I expect RDF toolkits to simply integrate Microdata parsers soon-ish (if we're good at one thing then it's writing parsers), and the Linked Data community gets just another taxonomy to link to. Schema.org owns the SEO use case now, but it's also a nice starting point for our more distributed vision. The semantic web vision is bigger than data formats and it's definitely bigger than SEO. The enterprise market which RDF has mainly been targetting recently is a whole different beast anyway. No kittens killed. Now go build some apps, please ;-)