Paddy Johnson's history of animated GIF art continues on Artnet; here is Part Two, covering what Henry Kaye and Corinna Kirsch call the "golden age of social media GIFs" and what I usually call the blogosphere era.* Johnson's essay covers solo and group blogs, pre-Tumblr, and includes so-called surf clubs. (Her generous mentions of my contributions to this madhouse are much appreciated.) Interestingly, she includes Dump.fm in this group, which makes sense in terms of the spirit of collective improvisation even though Dump didn't launch until 2010, when Tumblr was well under way. Its real-time image chat offered a kind of "sped-up Tumblr." And it's still going strong, with several generations of user sensibilities having rapidly cycled through over the last four years.
Another note: according to a Lorna Mills quote in the article, Mills and I were "originally influenced" by Sally McKay to go down the GIF path. McKay gave me valuable instruction and conceptual feedback when I started making my own GIFs but I had already been making "GIF art" consisting of arrangements of found GIFs. See, for example, "Cube tower slideup, by artech-x03, 80 times, an html/internet/curatorial/appropriation piece" from July 2003 and "Hug Emoticon Pyramid," from August 2003, the latter consisting of a found HTML arrangement of found emoticons, copied more or less intact from deviantart.com and represented as an art piece. (In a later post will screencapture those as a single GIF, since I can't rely on newsreaders and other rebloggin' apparatus to translate those patterns reliably now.) Am not suggesting these were radical innovations, but the strategies weren't as familiar then as they are now.
*roughly 2001-2010, when self-hosted blogs thrived prior to the mass movement to Facebook, but you could say surf clubs were 2006-2010.