The Dunbar Number

There seems to be a new openness to science theory in advertising thinking at the moment. Memetics is an obvious example, of how ideas are transmitted and received. Another that might have some merit is this piece from IT Conversations about the Dunbar Number - the 'cognitive limit to the number of individuals with whom a person can maintain stable relationships' and the formation and dynamics of groups. Could be worth a listen if you're planning an online community for instance, or want your email campaign to be considered a must-read by your customer?