Internet Rot is when internet searches result in outdated and old information and pages.
Internet Rot examples on Urban Dictionary:
: A complete desolation that will cover the United States should our nation be stupid enough to elect Barack Obama as our president.
George W. Bush
: He's our current president.
As you can see, these definitions are outdated, and therefore are Internet Rot.
Another example of Internet Rot: Googling
for 'make Firefox faster' mostly comes up with articles from 2004 regarding Firefox