As promised, here's a page for colorbars I've saved. Colorbars started off as a rainbow bar in support of gay marriage that eventually evolved into a general "love" graphic. Some people called them "love bars", but they were primarily known as "colorbars". Most of these would be accompanied by text that said "(x) is love" or "(x) is (descriptor of character, show, ship, etc) love". Some of these have text on the image themselves with examples. The "love" in this context was meant as a general "I support/like this thing!". These would go on profile pages on LJ and LJ forks, like InsaneJournal and GreatestJournal.
By the time LJ had its first big exodus when the first Russian sale happened and the fiasco with f-locked post content being partially visible on linked Facebook posts via a new LJ feature, the trend was on the decline and never really stuck around anywhere else people left to. DW was never as graphic-focused as LJ, and that only got worse after Photobucket fucked over all its users. That, and DW didn't start off with any sort of scrapbook the way LJ did. Tumblr's culture was very different in general, and places like Twitter and Facebook never really made sense for this sort of thing. I think these were a fun little thing to put on an about section, and we should bring them back, like buttons, blinkies, and stamps.