Given that Twitter was set up for these kinds of non-reciprocal follower/following relationships, it doesn’t come as a surprise that many users would use Twitter to follow breaking news channels and celebrities. The fact that almost 80% of these relationships are one-way relationships, however, does come as a surprise and hints at how Twitter’s mainstream users use the service more as a news medium than as a social network.
I looked at the slides, and I think the one thing they’re missing is @ replies. From the few celeb profiles I follow and have looked at, they don’t follow all followers back, which is understandable, but many engage with their followers. There is a second level of reciprocity that needs to be taken into account.
Would also be interested in seeing how the big accounts (profiles with a gazillion followers) and small accounts (people who have signed up, looked around and buggered off) skew the stats.