rsmiller510 (1051940) writes "Digg lost an astonishing 26 percent of its daily page views just one month after a site redesign that upset regular users. Facebook may want to pay attention to just how quickly things can change in the online social world." Link to Original Source
If it happens once, it's a bug. If it happens twice, it's a feature.
If it happens more than twice, it's a design philosophy.