Recently, Digg.com, the social networking site, introduced the ability to “Shout” brief comments to friend networks. The idea is that you can type a brief message and then send it to one or more of the people on your friends list. They can then reply, if they feel like it. In many ways it resembles the Private Message (or “PM”) functionality that’s common on many other discussion boards today. But in contrast to Private Messaging, which can really help a community, Shouts are a bad idea. Here’s why.

1. There’s no way to classify your friends on Digg, so there’s no way to only selectively receive shouts. Some of your friends like you for you, some like you for your stories, and some just want more friends on their list. But not everyone wants to receive a shout.

2. It’s pretty obvious that you can use shouts to inform others about particular stories - namely YOUR stories. Now, the goal of Digg, as a whole, is to share stories. And the best way to share is to get the story to the front page: many people have seen it, and many people approve of it. But this means that there is always motivation to shout your stories to as many people as possible in the hope that they will digg your story also.

3. Very quickly, this shout concept develops into a ‘digg for digg’ culture: you receive a shout about a story, you digg it, and then you know that the original sender will have the motivation to digg one of the stories that you shout to them. There’s very little cost to digging a story, but large potential cost of not digging: the ‘Shouter’ can see who has dugg the story and who has not. If you don’t reciprocate, this can result in one more person who diggs someone else’s story but not yours.

4. Ordinarily, the digg system means that good stories receive more diggs - so you should be able to tell a good story from a bad one by the number of diggs it has. But the ‘digg for digg’ culture means that even poor stories can receive diggs. This results in ‘digg inflation’, where a single digg is worth less because it’s so easy to get two or three diggs onto a story. Further, the diggs you do get don’t necessarily translate into more pageviews because the people who’ve dugg the story haven’t necessarily read it.

5. Eventually, Digg ends up with mixed quality stories: some are popular, some are not. Some are good quality stories, on good quality sites, others are not. And because the key quality signal, the digg, can’t be trusted, people will stop believing the story rankings they see. Users then spend time managing shouts to gain diggs, rather than writing better articles.

If digg.com was the only online social networking website on the Internet, none of this would be a problem. But thanks to open source software, for example, there are hundreds of open source social networking applications and scripts around. Anyone can start their own online social network. In fact, with the amount of interest at the moment in social network marketing, plenty of people are interested in developing social network applications. Digg should be careful to foster its community, not break it.