Did I DO something

to my settings, or is this just another of tumblr’s wonderful ‘improvements’ it just can’t help foisting on unsuspecting users?

And as I’ve been away awhile, it could well be either of the above, knowing me and knowing the devs here, but:

Whenever I click on another tumblr’s username, I get some #¤%”@?* annoying half-page pop-up on the right side of my screen.