Perhaps, movement. Many trending subjects right now, when considering exposure times, are night skies, light paintings, and ghosting. Themes of time, tangibility, and the supernatural abound, along with the big question of "Hey, how'd you do that?" Which can only lead me to the conclusion that many people are much more interested in process and aesthetics than content. That's not to say that it is condemnable to create work based solely in aesthetic pleasure, but creating work just to try out new techniques may result in work that is shallow of content and leaves little to discuss.
Everyone wants to buy pretty pictures. Unfortunately, not everyone wants to buy enlightenment.