i hadn't considered it that way, but tumblr really was addictive--was rewarding and self-directing--without any concomitant benefit. dw has the potential to encourage addictive behaviors (i refreshed my inbox abt 80 times this morning looking for a "hit"), but the benefit/utility is much, much higher, ie it promotes engagement rather than passivity.

it was great for fanartists, memers, and advertisers, but kind of terrible in all other ways for fandom.