Beginning as a plural variant of lol, Lulz was originally an exclamation but is now often used as a noun meaning interesting or funny internet content.\r
Lol -> lul; lols -> luls; lolz -> lulz.\r
\r
Lulz is the one good reason to do anything, from trolling to rape. After every action taken, you must make the epilogic dubious disclaimer: "I did it for the lulz". \r
\r
This has been pioneered by encyclopedia dramatica, famous for posting a fake craigslist add and then listing the personal info of those who responded.
> "Why did he post a suicide note on livejournal before killing himself?" "I hear he did it for the lulz."