Social silos will work to a certain point.  Programs will develop in isolation.  Tools will be bought. Resources will manage, optimise and in some cases, duplicate effort.

Then they'll be a point where suddenly a company realises that without great content, sales can't share anything (Hint:  Sales reps who regularly share content are 45% more likely to exceed quota)

Marketing will realise that without insight and authentic content from the experts within their business, lead conversion will drop.

All studies are showing that a united front between Marketing and Sales will drive a best-in-class approach to social media.  

More than that, this is what customers want. Customers are more likely to purchase from socially active companies.  That's true.  But imagine the competitive edge you get when a company joins the dots between all their social programs.  Unbeatable.