Johnny got some new cards, so the other kids come over to see them after school. The cards are social currency. We think of a medium as the thing that delivers content, but the delivered content is a medium in itself. Content is just a medium for interaction between people. The many forms of content we collect and experience online, I'd argue, are really just forms of ammunition, something to have when the conversation goes quiet at work the next day.
Social currency is like a good joke.
Sure, for a start. Trying to memorise it so that we can bring it somewhere else. He tells good jokes. Think of this the next time you curse that onslaught of email jokes cluttering up your inbox. The senders think they've given you a gift, but all they really want is an excuse to interact with you.