They already have. Check out our site, http://trendistic.com/ . We have been tracking trends on Twitter for the past year, and we've seen all sorts of phenomena, from grassroots campaigns: http://trendistic.com/iranelection/_90-days 5o get-followers-quick spam, politics, etc. http://trendistic.com/followers/_180-days (click anywhere on the chart to see what people were saying at the time).