The first is Whatever made you think it was your data anyway? by Steven Poole. I've been reading his work for ages, and love his dry, cynical and insightful style. The stand out line from this piece is “If you’re not paying for something, you’re not a customer; you’re the product being sold”, which is characteristically brutally accurate. If you too enjoy his style, I also heartily recommend his book Unspeak, which looks at the tactical use of euphemism in politics and the media, and is fantastic. I have a copy that I'll happily lend to interested Oxford people.
The second essay is also rather marvellously named: The Social Graph is Neither by Maciej Ceglowski. It's addressing a similar problem from a different perspective: asking what it means to make your relationships public, and what makes for a good social network. I wasn't aware of this guy until someone linked me to him today, but (amongst the technical stuff about his site) he's also written some other interesting stuff about social networking: the influence of fandom in this case, for example.