I get asked quite a lot, “Why do you put sloths in pictures of James McAvoy?” and “What started this?”
Well, what started this Tumblr was a post about Tumblr popularity in my journal (or rather the lack of it as far as my personal Tumblr goes) and I mentioned that if I had really wanted to make my Tumblr popular I should have chosen a popular subject and post regularly (rather than infrequent posts of crappy doodles and fanart in mine).
I had just encountered the “Michael Fassbender with pugs” Tumblr, that even inspired Yuletide fanfic (so really that one is to credit from my perspective for the “celebrity+ animal formula” because I first encountered it there), and had seen an article about the rising popularity of cute sloth pics compared to cat macros (with these sloth sanctuary videos and all that). So the quintessential example for popular Tumblr themes that popped into my head was “McAvoy + baby sloths” as a winning combination.
So then I made a picture pasting a sloth together with McAvoy as a proof of concept, and it turned out to be rather fun, so I then couldn’t resist starting a Tumblr for real (though sticking just with baby sloths turned out to be impractical for image sources, so it expanded to sloths in general).