Your graph only three data points. Lets say hypothetically the traffic was 100m requests/yr and dropped off immediately after the redesigned you'd still expect to see something like
2009 - 100m
2010 - 60m
2011 - 0
This page has some graphs with more data points but the tl;dr is traffic was down by more than 50% within a month.
Admittedly reddit's growth was much more muted but Digg did really just destroy the site.
Indeed, that's much more of a "cliff." Sorry, I should have spent more time trying to find that more-detailed graph I saw earlier. But as you say, it took a long time for Reddit to grow. And Digg's remaining activity was surprisingly stable for a "dead" website - half the users seem to have stuck around indefinitely.
Your graph only three data points. Lets say hypothetically the traffic was 100m requests/yr and dropped off immediately after the redesigned you'd still expect to see something like
This page has some graphs with more data points but the tl;dr is traffic was down by more than 50% within a month.
Admittedly reddit's growth was much more muted but Digg did really just destroy the site.
Indeed, that's much more of a "cliff." Sorry, I should have spent more time trying to find that more-detailed graph I saw earlier. But as you say, it took a long time for Reddit to grow. And Digg's remaining activity was surprisingly stable for a "dead" website - half the users seem to have stuck around indefinitely.