Many people believe that this Family Guy episode predicted, caused, or cued the Boston Marathon bombing. While it may not be true, since the episode occurred before the bombings, it still gave rise to conspiracy theories. By looking into the comments of this video, I have found such believers. The hilarious part is that Family Guy performs this sort of stuff all the time. It's all one rather large coincidence.
Of course, this is my own personal opinion and thoughts. You could believe that this was a conspiracy plot or prediction. You could believe that Seth Macfarlane predicted this, after all, this has happened before with Family Guy. They've 'predicted' the 9/11 attack as well. The question is: Is it all true to you?