I'm pretty fascinated by something that's been happening on Twitter for a while. If you look at the top trends on search.twitter.com there's always something like: #tacky #youwerecooluntil #songofthedecade etc. Facebook also had the bra color meme going on/still going on: http://mashable.com/2010/01/07/bra-color-facebook-status/From a scientific and almost investigative aspect, what makes things like this trend? This is different than things like earthquake or certain news events that trend due to their nature ie- they happen at a certain time and impact a lot of people who talk about it.