We see the term the "second screen" thrown around all the time, a concept that refers to the belief that the immediacy of social media across phones and tablets makes television watching a communal experience. The thinking goes that Twitter and Facebook are portals into our consumption habits, allowing us to hurl breathless critiques--and, sometimes, spoiler alerts--into the digital ether. We've also seen Twitter flirt with TV networks. The service has reportedly spent "hundreds of millions of dollars" developing a rating system similar to the traditional system long used by the advertising biz. And it's widely held that this is why Facebook adopted some of Twitter's more popular features, like trending topics and hashtags. But a new report suggests that the second screen's overall footprint might actually be smaller than previous metrics suggested.