Dubbing, also known as rerecording, was first used in films to fill in blank audio, or for translating purposes. The genre of dubbing over footage for the purpose of creating something new was born from this practice of dubbing for the sake of editing. The name of the first feature length film that was dubbed for the purpose of creating something new, in other words not for editing, is escaping me now, but I vividly recall watching it as a child and recognizing its creativity and uniqueness. Before the web, plenty of films were dubbed for editing purposes, and almost any film can found dubbed in another language, so the history of dubbing is vast, but the history of clip dubbing is more specific.
The first online dubbed video I can find comes from the YouTube account dayjoborchestra, and it was uploaded in 2006. The video is a dub of news footage with several different characters. The creators were clearly not going for accuracy with their dalogue, but instead were trying to be vulgar in order to give off the essence of humor, which they also failed to. Clearly this video is an early attempt at clip dubbing, a genre that has now been nearly perfected by BLR.
I would surmise that the target audience for dubbed videos was originally young people, due to the vulgarity and lack of editing in early videos. Young people, when browsing through online videos, are generally more likely to watch a vulgar, less-than-perfect than an older person. However, no that BLR has become the main provider of dubbed videos, I would say the target audience has shifted to just about anybody looking for a funny video. BLR has upped the quality of video and really opened the genre to the general public.
There are three main clip dubbers online: Bad Lip Reading, dayjoborchestra, and jaboodydubs. Of the three of them, BLR is the most recent on the scene, and clearly the most creative and original of the three. As well, BLR has the best quality video and audio, and it is clear the BLR puts more effort and thought into their videos than djo or jd. BLR is also still producing videos, their most recent video having been uploaded on January 15th