Why is it so hard to contact people on some social media sites? On Digg, for instance, you can send members a “Shout” that typically appears as a public comment on their profile page, but you cannot send a private message. Mixx, a Digg clone that we like, is adding private mail and group message boards to its site tomorrow. Members will be able to send mail to any other member, and block messages from any member as well. Every group will also have a message board to discuss a general topic not related to any one story. These are pretty basic features that somehow got lost as lean-and-mean social media sites started to take off. The only other social news site that has mail is Propeller, which is owned by AOL.

Are social news sites better off keeping everything above board and public, or do private messages foster a deeper sense of community by strengthening individual links between members?

One reason not to allow private messaging is that it could be used to game the system. The most active members might constantly be getting private messages encouraging them to vote up particular stories. Sites like Mixx and Digg are all about collective action, and they should be careful not to dilute that emphasis. But sometimes you just need to contact someone, and there should be an easy way to do that too.