Social is not a new type of icing. It's a new way of thinking about your cake.
I then got a number of good responses. From Travis:
Actually, social is a new way of deciding what to make -- as Marie Antoinette found, the people might not want to eat cake.
And then from Justin:
Social is a cake fight. Everyone has a cake, and they're all throwing it at each other and trying to dodge.
Fun stuff, and a good excuse to make a summary blog post.