as much as possible of a particular website
, then tell your friends about it so that you're not the only one who spent all day reading comics
The first productivity virus to be so named was the User Friendly Productivity Virus. New fans of the web comic strip User Friendly often enjoy it so much that they read the entire corpus from beginning to end, ignoring actual work. The virus spreads as each new fan emails a few strips to their friends, who then get hooked.
Any sufficiently sticky site can cause a productivity virus: superbad, Hot Or Not?, and so on. I currently, for example, have the Sinfest productivity virus.
For example, Mr. Option writes in Leisure Town:
"It was a deer in headlights kind of experience. For about two hours, I was suddenly rendered incapable of doing any work or looking away from the screen."
This is the essence of a productivity virus.
Proof of the existence of an E2 productivity virus is left as an exercise for the reader.