Stands for Laugh Quietly Please: the intelligent person's alternative to lol.
Person 1: lolz rofl omg it woz zo funny lyk xoxoxoxox
Person 2: lqp
When some idiot posts or says something like 'cool story bro' or 'lol i found that funny' or what not. 'Low Quality Posting'.
Guy 1: Lol I had the best day 2day. I got laid then I had lots of fun!!!!one1e1on1! <Insert details of day>
Guy 2: Nice
Guy 3: Fucking LQP faggot