The girl from the creepy ex-girlfriend meme actively capitalized on her stardom. It seems that the sociological phenomenon of involuntarily going viral is becoming more well-understood.
If you mean Overly Attached Girlfriend [1], she framed the joke intentionally, in terms of its visual look and its connotations, in exactly the form that took hold as a meme.
Contrast this with memes where a picture caught the eye of a photoshopper who then decided what joke to write on top.
It was her own sense of humor from the start. Good on her :)
Yes totally. Though didn't that girl intentionally create the creepy ex-girlfriend persona? It's a little bit different than Rebecca Black who created something in earnest but then made the best of having it taken as a mockery.
It's hard to predict the path a particular meme will take once it has gone viral. Compare say "creepy girlfriend" to "scumbag Steve".
If you can predict with good to absolute confidence where a particular meme would go, then you have something extremely valuable that any marketing dept would go for.
Remember, most of these things happened unexpectedly to the people involved. I think you would be hard pressed to find anyone that a) knew in advance what would happen and b) wanted it to do so deliberately.
Making the best of a bad situation is not understanding this sociological phenomenon.
Contrast this with memes where a picture caught the eye of a photoshopper who then decided what joke to write on top.
It was her own sense of humor from the start. Good on her :)
[1] http://knowyourmeme.com/memes/overly-attached-girlfriend