> ...pursuing trademark infringers... That's the part they should be apologizing for. Unless their business is actually getting hurt in any way (is someone selling fake Chinese made Tumblr t-shirts on the black market?), this is just a systematic exercise in corporate bullying. They shouldn't be engaged in this in the first place. Tumblr is not friggin' Nike.
I wouldn't be surprised. Tumblr just sold for a billion dollars, remember? That's certainly a brand worth protecting.