I've been thinking about how social media works.  For example, applying game mechanics to understand participation, thinking about users vs. customers, and deconstructing ego traps in PR campaigns.  This analysis makes me wonder if social media marketing matters and if so, does it scale.

I thought you might benefit from some of my background research on these topics.  And I'd appreciate your help in curating this list by providing more details and submitting additional cases.

>> Last update: 3 September 2008
>> Total brands: 123

Examples of companies using and being used by social media marketing:

[Notice anything missing?  Leave a link and description in the comments below.  I'll add to the main list on a periodic basis.]

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1 Jeremiah Owyang's A Chronology of Brands that Got Punk'd by Social Media
2 Mashable's 35+ Examples of Corporate Social Media in Action
3 Forrester's Groundswell Awards, 2007 and 2008
4 Mack Collier's Company Blog Checkup Series
5 Social Brand Index - Twitter