Board Thread:General Discussion/@comment-8161155-20140516200942

Okay, so I know this has been discussed a thousand times before. But I'm not posting this just to say "It's Roderick." Here are some clues as to what the name might be. Idea #1: The name must be embarrassing enough that he would rather go by "Dipper".
 * "Mabel" is a pretty old-fashioned name. Maybe Dipper's name is equally old fashioned, but much weirder ("Algernon")
 * Or maybe their parents wanted to rhyme their names or make them similar, giving Dipper an awkward name.
 * 2: One of Dipper's friends, or someone he knows has the same name as him, so he changed it so they wouldn't get confused. 