YouTube isn't a profitable business even with revenue of $4 billion in 2014.

The culprit, apparently, is that most users arrive at videos via links, rather than daily visits to the YouTube homepage where Google could charge a premium for ads. WSJ also reports that the site's reach isn't very wide either, with one source's estimate that nine percent of viewers account for a whopping 85 percent of online-video views. That makes it a much less appealing audience for advertisers than traditional TV programming, despite the outfit's increasing investment in original content.