A popular variant spelling of lurk more. It is an expression used when someone demonstrates their ignorance of the customs and social expectations of an online community, or otherwise makes an idiot of themselves online. Its use indicates that the person so instructed should gain familiarity with the community before posting further.
annoying_n00b: LOL @ my genius! I am the greatest! Surely everyone loves me by now.
everyone else: LURK MOAR
Often used to tell new or inexperienced users on 4chan's /b/ image board to search further into the depths of /b/ to find things such as the origin of certain memes, or just to stop posting until they are more familiar with /b/.
Noob: LoLz sniper kitty roXors my soXors. who make it in first place?!/!!1?
/b/: LURK MOAR.
Something you say when you're creeping on someone, and want to freak them out; Something one says to such a creep.
*Mark Zuckerberg likes your picture from 10 months ago*
Mark Zuckerberg: lurk moar
One night stand: awh, that status about you having poison ivy all over your crotch was so sad!
You: Lurk moar, dude! That was seven months ago!!
A phrase used when a lurker (one who hangs around a forum, etc, and very rarely posts or contributes in any other way.) makes a stupid, off-topic, or otherwise random and nonsensical post or comment.
Masterchief1112: In 5 days, we'll be hosting a gaming tournament based on Half-Life and Halo. Anyone who wants to join just give me the word.
GordonFreeman2042: Wow, that's totally gonna kick ass. I'm in!
Wildwoody69: I pee in butts.
Masterchief1112: OK, you signed on a year ago, you haven't posted anything since, and you come here with this faggotry. LURK MOAR!