Having seen a number of 25 random things being written by my Facebook friends, reading this article was very relevant to me. Its main point is that the behavior of the 25 random things simulates that of a virus' growth, in fact it "was strikingly similar to a virus outbreak, including mutation and epidemic progression."
From the same article, Lauren Ancel, a biology professor at the U of Texas explains that "'25 Things' authors can be seen as 'contagious' under what’s known as a 'susceptible-infected-recovered' model for the spread of disease." and that "on average, each '25 Things' writer inspired 1.27 new notes."
I've actually thought about writing my own version of 25 random things as well. But I find no use for it, so I won't succumb to the virus.
If it employed a marketing message, then this is truly viral marketing.