Email privacy
Someone once told me never to say in email anything I wouldn't want to see on the front page of the New York Times. I've never been good at following that advice, but of course email is easy to forward, and it's always possible that something you intended to be private will end up as an accidental privacy spill. That's an interesting LawMeme piece (long! in fact, so long that I haven't finished reading it yet) about a journalist whose conference report, sent via private email, ended up on the web (and being discussed by the denizens of MetaFilter). I like the article author's point of view: in favor of information spread in general, but wary of claiming that it's an email-writer's fault if their message ends up going public. Some good stuff about social norms 'n' stuff.
Here's an argument from that article which, though flawed, might be interesting food for thought:
As long as the average number of forwards per recipient is greater than one—no matter by how little or how much—the laws of probability tell us to expect a nice happy power-law curve zipping up towards infinity.
This is the second or third interesting piece I've seen on LawMeme recently; I oughtta wander over there more often.