Digg is growing and I could see its pain in promoting new stories. Out of 40,000 submissions a day, which ones do you promote? I find that Digg’s recommendation engine solves two rather interesting problems:

1. People do not like sifting through 40,000 stories a day
2. People are submitting irrelevant things just to promote spam or perhaps just to stroke their ego if those stories are promoted to the front page

The recommendation engine is neat in that it solves both problems with one mechanism. The first is obvious — users get to read at what others digg, specifically from users that share similar interests.

The second problem is solved in the process of the first. If the trend is that users mostly look at recommended submissions, they first need to find affinity with diggers and submitters, and vice versa. Thus spammers have much reduced chance of hitting the front page unless they are actively engaging in a community and submitting relevant stories to the community. Out of band pages are indirectly barred receiving much attention. It still does not solve the problem of trolls, where stories praising Obama and slandering McCain abound the top stories list. But that is something diggers want to see and not inherently problematic. So the natural progression on steroids in the case of the recommendation engine is a virtuous one.

Now here is an interesting paradox. I am not a Digg user myself. I will submit / have submitted a story on this post. There are two outcomes:

1. It receives enough diggs and makes to the front page
2. It does not

If it does, then my theory is ultimately flawed, and thus should not have been worthy of being on the front page. If it does not reach the front page, my theory is (at least partially) true, and thus (partially) deserves to be on the front page. Fun thing to think about on a sunny Sunday afternoon.