You know social media is mainstream when the big accounting firms get on the bandwagon.

This evening I attended a meetup for Michael E. Raynor, author of the new book, The Strategy Paradox. I learned of it from HeyLetsGo, a regional social network. I wanted to meet Raynor since he co-authored one of my favorite business books, The Innovator’s Dilemma and his new topic sounded like it might make interesting fodder for a blog I write on innovation.

It turned out, though, that the social-media aspect of the meetup was as interesting as the author. The event was an experiment for Deloitte. Held in a small upscale restaurant in downtown Boston, it had no guest list. Anyone who showed up was free to attend (and with open bar and a fine selection of hors d’oeuvres, it was a bounty for those who did). Promotion was through an announcement on PBWiki and news of the event spread entirely through word of mouth. Mark Doerschlag posted the notice on his MarksGuide.com, a blog devoted to professional networking, posted the notice on HeyLetsGo, which is how I learned of it. Anyone could have come: in that respect, it was quite different from the tightly controlled press events of yesteryear.

Deloitte reps delivered a short presentation highlighting the experimental nature of the event. There were no attempts to sell the company’s services. Everyone got a free copy of the book. I’d say there were about 30-40 people there.

I found the audience to be of surprisingly high quality, given the lack of restrictions on attendance. In addition to spending some quality time with the author, I spoke with several other attendees whom I had never met before. All were business professionals with a strong interest in social media and in the strategy-focused topic of the book. It happened that nearly everyone I spoke to was self-employed. Several appeared interested in the networking aspects of the event. All were bright and inquisitive and the type of people who will probably blog about the book.

I don’t know if this meetup will ultimately prove successful in promoting the book, but I was impressed with both the attendees and the discussion. I’ll certainly be looking at applying this idea to marketing my own book, which is due next month. For an event with so few restrictions, I thought it was a notable success and a testament to the power of word-of-mouth marketing.