That explains this line: "MySpace also has a lot of good data, but not all of it. Likewise LiveJournal, Digg, Twitter, Zooomr, Pownce, Friendster, Plaxo, the list goes on."
wow, only twitter is still relevant from that list
LiveJournal is still quite alive in certain parts of the world... But yes, FB ate 'em all.
Digg "pivoted" and I like their emails now, pretty nice content usually.
Coincidentally I had this open in a browser tab: https://xkcd.com/256/ (map of online communities in spring 2007 showing Facebook still smaller than LJ)