The authors explicitly go after some of the basic questions in memetics, writing:
So can memes really be modeled as genes? After all, Richard Dawkins originally coined the word "meme” to draw the analogy to genes when describing how ideas or messages replicate and evolve. How would one test the hypothesis that memes undergo a process akin to biological evolution? First, tracing biological evolution is notoriously difficult because one must discern the lineage of specific genetic sequences through generations, without having the genetic sequence of many intermediate instances. But when studying Facebook memes, we have a very unique opportunity to actually trace when copies and mutations occurred, and these are the two basic ingredients in the evolutionary process.
We’ve observed a number of remarkable parallels between how information evolves in a social network and how genes evolve. Drawing these parallels simply hasn’t been possible before for lack of large-scale data containing the evolution histories of many memes. Here we examined near-complete traces of hundreds of memes, collectively comprising over 460 million individual instances. Although the study is limited to just the Facebook context, and just on format of meme (textual status updates), we believe it provides useful insight into the behavior of ideas transmitted via social ties in general.
Here's one of the images from the article. The caption says: "A tree showing the lineage of each variant of the 'no one should' meme".