Social Media Measurement Roundtable: What number of participants and format makes for the best discussion

Yesterday I proposed that we organize a roundtable on social media measurement and metrics. The response I’ve received via comments on the blog post and email has been overwhelmingly positive.

So, let’s move forward with this.

Number of participants 

As a first question, what do you think is the maximum ideal size for a productive discussion? Is it 15, 20, 25, 30?

In choosing the ideal size, I think we need to balance opportunity to participate with the quality of the experience for the participants. The group should be small enough that individuals are able to exchange points of view. On the other hand, if it is too small, we risk excluding participants with valuable perspectives to share.

Format

How about format? My initial thought is that we should have one discussion table for the entire session? Is this a good idea? Or would another format work better? Perhaps a common session to open the day followed by breakout groups on specific topics before reconvening for a general discussion?

Your opinion? 

What do you think is the best size for a discussion of this sort? The best format?