Variations on a theme:
Membership sells - but cuts both ways. Differences kill relationships, but prove to a potential new customer that you have something he cares about in common with him, and you're halfway to closing the sale.
What does knowing about miniature long haired Dachshunds have to do with selling Linux support licensing? Nothing, unless the customer manager you're talking to happens to own Am Cdn Ch KingFisher's Royal Guardian CDX, then it's your ticket to a decent monthly report.
What does knowing you can NFS mount a 24Terabyte "thumper" array on AIX for less than the cost of an IBM controller set buy you if your customer thinks a Shark/ESS array is a hot piece of "mainframe class" gear? An invitation never to darken his doorway again.
Ignorance expressed as membership is self-perpetuating: you can't sell advanced technologies to people who're more than two generations behind your own bleeding edge because the people you hire to front the product will turn off the customer - and for the same reason you can't retrain a sales force focused on data processing to sell Unix without first compromising Unix.
Success expressed as fellowship is self-perpetuating too: hire a science grad without the experience to have developed bad mental habits, help him succeed in a difficult Linux install, and you'll have made a lifetime Unix evangelist - one you can teach new tricks to, at least until something replaces Unix.
Bottom line? knowledge has emotional mass: it attracts like, repels difference, and expresses momentum according to some super-linear model based on the number of people in the group - meaning, from a product sales perspective, that if you step outside the avalanche zone you're going to be headed downhill on your own.