PETA responds to the Super Bowl commercial advocacy controversy by pointing out that CBS rejected a PETA advocacy ad for the Super Bowl in 2004 (in fact, the same CBS spokesperson is quoted). In 2009, NBC rejected a PETA Super Bowl advertisement, and also rejected a PETA advertisement for the Thanksgiving Parade. Don't cry for PETA: they rarely have a difficult time finding ways to get attention. But this trend does show how far out of the mainstream vegetarian advocacy really is: major networks find reasons to avoid the subject for major broadcasts, even when an advocacy group wants to pay the network to run an advertisement.
This gets at why I believe vegetarians and vegans are on the same side. You respond to the society you live in. In a different world, those advocating that we merely not eat animals and those advocating that we never use any animal products might be on opposite sides. But in the world we live in animal exploitation is everyday, the overwhelming majority of people eat meat, and mainstream society views both vegetarians and vegans as fringe outsiders with radical ideas. As it is, vegans and vegetarians respond to the same culture, with similar purposes and from a similar place.