I've been thinking about rats and levers a lot lately because of that stupid title text change (Twitter has it, too) - even if I'm not on the Tumblr site itself, if I have it open in a tab while I'm doing something in another tab, that title bar changing to (1) or (5) or (40) pulls me back to Tumblr. (I can see it updating while I'm writing this, and it's SO HARD not to go check what's changed!)