Post script:

Business and IT strategist, and next-gen (Enterprise 2.0) expert Dion Hinchcliffe (with the Dachis Group) tweeted me a link to his "related" article on ZDnet after he read this blog. I think Dion's piece is a great complement to my thoughts, above. His is titled "Is the window closing on enterprise customer communities?" ... I recommend it and am proud to have my piece affiliated with his in some small way.

Here's a link:
http://www.zdnet.com/is-the-window-closing-on-enterprise-customer-communities-7000014884/

While there, you ought to follow Dion for more of his wisdom - he's an expert on many topics, with access to rich research and a range of case studies, and often shares forward-looking insights.