Kashmir Hill, Forbes' indispensable privacy blogger, posted this chart today, drawn from a survey of employers. Three things to note. 1) 95 percent of employers say they use social media sites to ferret out more information about job candidates. 2) If these employers informed these job candidates why they were dropped, Facebook as we know it might not exist.
That's not because social media is bad for job candidates, per se, but rather that the sense people have that they are just talking with their homies would evaporate. It would become clear that Facebook is, in fact, a quasi-public forum in which what you say attaches very strongly to your identity. It's the persistence that makes it different from "real life" and it's the persistence that Timelines is going to highlight.