> Reddit also has the advantage of doing it during a major UI shift - it's easy to justify design changes when everyone is heading for mobile browsers anyway. Digg didn't have that excuse.

On the contrary, Digg’s UI changes were happening when “Web 2.0”-hype was peaking, including bold new web-design trends - many sites were actively redesigning themselves with a brighter theme and better visual-effects: this was around 2007-2010 when IE6-support was starting to be discounted by tech-oriented websites so they could start using new CSS features and alpha-channel PNG images that IE7, Firefox, and Opera supported.

I argue that the changes to their recommendation algorithm - and the introduction - and eventual promotion - of mainstream news (especially sports news) meant that their early users: technology news readers, lost interest in the site. The redesign of the site was a contributing factor, but a bad redesign is nowhere near as damaging to a site’s popularity than it losing relevance to its core user base.