I think "Famous Gaga" is a pretty decent example of social reflection in the form of art. Her videos and music sell, which is a pseudo-representative commentary on what society (at least those members of it who buy her music, millions worldwide) consumes in the form of "cultural" forms of expression.
There's not much to over-think here. She's a cultural phenomenon because she shouldn't be doing well if culture rejects her outright "freakishness" and vulgarity. Not only does the culture around Gaga overlook it, they practically go "Gaga" for it. They buy it largely because of its freakish vulgarity, because this personae she creates with her music and her appearance appeals to some people. And these people are influential in turning other people on to her music (and perhaps onto the culture it appeals to), thus the huge following she has now.
But I think it's mostly the cultural aspect that interests me most. If you reject the culture or the values presented therein, you're likely to find "amateur Gaga" more appealing. Either way, she has tremendous talent and does an outstanding job of connecting her music to the culture that she appeals to in society. I think this is what's important to understand about her. She's not some cheap parlor trick to appeal to an audience like so many other pop artists tend to be. She's genuinely skilled, genuinely appealing within the culture that consumes her work and understands her, and that should be a pretty good measure of her influence in the broader context. I happen to think that if you identify yourself with the culture Gaga appeals to, you're represented well by her. There's nothing wrong with that.