From readwriteweb.com, an area chart showing the decline of Tech stories made popular on digg.com. Although initially the front page of digg.com was totally dominated by Tech stories and the primary users were tech geeks, the World & Business category is now the reigning king with the most stories made popular.
To put this into context, on 1 January 2006 tech stories made up 78% of the total popular stories (i.e. stories that made it onto the digg frontpage). By end of March 2008, that percentage had dropped to 18-20%.
Here you can see the same information charted as total number of stories made popular instead of percentages.