In another in the growing number of comics that are making the transition from Web popularity to trade paperback collections, 'Piled Higher and Deeper,' a daily comic strip by Caltech instructor Jorge Cham that focuses on the life of grad students, has been collected into two self-published trade paperback volumes that have sold 12,000 and 7,000 copies, respectively. 

The Website serves a very respectable 3.5 million page views a month, which while not up to Penny Arcade (see 'Penny Arcade Brings in Bucks') or Megatokyo levels, still means that there are a lot of people out there that are following this strip online.  It's also published in the Stanford Daily and a number of other college newspapers.  Pop culture retailers near college campuses may find it worthwhile to stock these books, which are available through at least one major book distributor.