Citations:ROFLOLer

Noun: "(Internet, slang) a person who uses the expression ROFLOL (rolling on floor laughing out loud)"

 * 2007, Jenna Wortham, "Famous Internet Memes to Gather at ROFLCon 2008", Wired, 7 December 2007:
 * Calling all LOLers and ROFLOLers – get your geek on! In celebration of all the treasured gems that are internet memedom, a group of Harvard folks are throwing what’s bound to blow up into the the biggest nerdfest outside of a Star Trek Convention.