Do you read German? Then I have two recommendations for you.
First, go read this fresh interview with the German social networking guru Klaus Eck. It's about "a life long job application process".
Second, go read the book "Karrierefalle Internet" ("Career trap: Internet") by Klaus Eck. That book is what the interview is all about.
Klaus Eck's basic statement is "go manage your online reputation before others do it for you". He notes that he's seen plenty of Angst amongst social media newbies about how they're presented online, with the end result that those who are afraid don't do anything in their defense (i.e. they don't establish a web presence of their own), and are thus at the mercy of random comments on their real life turning up in the net. To me, the negative header of the book is rather a reason not to buy the book ("I want to steer clear of Internet, as it is a trap"), but perhaps he's right that fear sells ("I want not to be trapped by the Internet, so I'll buy the book").
At any rate, I bought the book, and I did so after noticing it by coincidence at the physical bookstore Hugendubel at home in Munich. So perhaps he's right that FUD sells.
As for the insights and structure of the book, I can only recommend it. Klaus has good suggestions and a good logic. He has thought of many Web related things I haven't, and I find myself concurring with most of those. I would disagree mainly on his recommendation to use Twitter only in one language. Nope. The web should reflect real life. What this means for your presence on Facebook, or Twitter, or LinkedIn, or anywhere is this: If your real life is multilingual, then so should your web presence be. Sure, in real life, I don't speak Italian to Russians. But on the other hand, I don't see a point in keeping it a secret from the Russians, that I have an Italian blog. Analogously, if you follow my Twitter feed, you'll see tweets in several languages. I pick the language based on who I direct the tweet at, and if you don't read the language in question, then it's likely that the contents are not that interesting for you, either.
Finally, I'd like to thank Klaus Eck for being one of the key sources of inspiration for my series of blogs where I "share my experiences improving my online manners through social networking websites, many of which are powered by MySQL.". So far, I've done Dopplr, Picasa Web and Facebook. More to come, with time.