Don't forget the big ROI capability
Great blog but you are leaving out on of the most powerful ways of creating value through social media - corporate events and sponsorships.
Many of the Fortune 500 spent millions of dollars on events, venues or activities which can be very highly amplified through Facebook or Twitter if they create an ambient social media experience.
The success of the social media experience that Vail Resorts created at their mountains (EpicMix) is a great example, but just looking at what Facebook does at all their events, Harley Davidson did at Bike Week and Lexus will do next month at the US Open Golf Tournament. An event can be shared in real time (thanks to technologies like RFID and NFC) without the friction of using a mobile phone or tablet. Pictures are captured automatically with the wave of a tag or bracelet and then posted in real time on Facebook, for hundreds of people to see and engage with.
I wrote a blog two weeks ago about best practices around social media your readers might enjoy - and I'm happy to talk more if you are interested and want to see some case studies. Here is the blog http://www.dwinq.com/social-blog/bid/144300/The-cost-of-social-media-mar...
Here is a great example for Major League Baseball that ended up more BBC like than your average video (YouTube - http://www.youtube.com/watch?v=zTxjSP07JLU )