As someone who used Digg and Reddit from their infancy I have been able to observe when and how Digg fell from #1. I don't think they failed because they were having delusions of grandeur.
The 1st mistake that Digg made was the introduction of power users. As a power user your stories were artificially boosted to the front page. After this happened, I noticed a huge decline in quality where the front page became mostly populated by articles from cracked and huffingtonpost. This quote from another user summed up the situation.
In version 3 around 100 diggers ran 80% of the front page – to get on the front page you had to cover Kevin getting a blow job from Stallman, or get a power user to submit your story. At that point Digg was not a democracy at all, but a curated list by paid Digg pros who shilled for hire. If you were a nice guy, or a tech publisher, you had power digger friends who would submit your stuff for you for free.
Then there is the 2nd mistake that everyone knows about. Digg 4.0, the last mistake that finally made Reddit bigger than Digg. Large domains Engadget and Mashable flooded the front page with their auto-submitted stories. It was then that Kevin Rose betrayed the power users for large publishers, just as he had betrayed the regular users for power users many years ago.
If Digg had not done any of this, there would have been a very good chance that they would still have been the largest aggregator today.
Please; power users were controlling the content on the site long before they turned 3.0 on. It was a well known fact that a small minority of users controlled the vast majority of the front page content (mrbabyman, for instance).
The 1st mistake that Digg made was the introduction of power users. As a power user your stories were artificially boosted to the front page. After this happened, I noticed a huge decline in quality where the front page became mostly populated by articles from cracked and huffingtonpost. This quote from another user summed up the situation.
In version 3 around 100 diggers ran 80% of the front page – to get on the front page you had to cover Kevin getting a blow job from Stallman, or get a power user to submit your story. At that point Digg was not a democracy at all, but a curated list by paid Digg pros who shilled for hire. If you were a nice guy, or a tech publisher, you had power digger friends who would submit your stuff for you for free.
Then there is the 2nd mistake that everyone knows about. Digg 4.0, the last mistake that finally made Reddit bigger than Digg. Large domains Engadget and Mashable flooded the front page with their auto-submitted stories. It was then that Kevin Rose betrayed the power users for large publishers, just as he had betrayed the regular users for power users many years ago.
If Digg had not done any of this, there would have been a very good chance that they would still have been the largest aggregator today.