Twitter, like Faceboock, reddit, or like google are TODAY phenomenon. The way Myspace was a few years back (every artist was supposed to be there), or Second Life (politician had to have a presence there), Digg, or some old aggregator search engine, I already forgot about.
Those stuff (except for google who reached on a so larger scale it's scary) just exist cause of their userbase. People tweeting, liking on facebook, searching on a webpage, upvoting, etc...
If the majority of the people using those website just stop, those site lost ANY value. They worth NOTHING in themself. They are convenient way to do something, but anyone (like MK here, or google+) can come up with a new way to do what they do.
So studying about how those stuff exactly work tell us more about their internal (or emergent) mechanic than the way people really communicate.
Studying meme is interesting cause it's about the creation, and propagation of a phenomenon. Studying how the same meme went through twitter, is just about twitter and its "rules". That's Something of tremendous value for the twitter programmers (so they know how their system actually impact people), and so they can eventually make money with their website. It tell nothing about the end user. Nothing about How people actually spread news (just how that happen on a particular website).
So I suppose those research are funded by twitter, or eventually by someone trying to build a new twitter. I'm not "opposed" to that kind of stuff. It's even kind of funny to learn some trivia about twitter.
But in the end I cant help but feel sad that some people lost their time over such a study. It's like someone in 2000 trying to explain how the hamsterDance webpage works.