Since 2005, I’ve been a proponent of CSS frameworks. I was even the leader of an open-source project, AppFuse, and during that time, we held a design contest (using Mike Stenhouse’s CSS Framework) in order to provide themes for our users.
Over the next few years, a few new frameworks came into my awareness; Blueprint in 2007 and Compass in 2008. None of these frameworks, however, could hold a candle to Bootstrap. When it first came to my attention, it was called Twitter Bootstrap—invented in 2010 by Twitter employees Mark Otto and Jacob Thorton. To quote their words from "Building Twitter Bootstrap", Issue 324 of A List Apart: