Looks like Pixelfed's growth spurt is slowing down. Absent any new external stimuli I'm guessing it'll stabilize around 200K to 300K monthly active users -- over a hundredfold order of magnitude from what it was just a month ago.
Long and short... Pretty much all the big tech heads sat in the front at trumps innaugeration, including Zuck. Shortly afterwards there were a bunch of coincidental "bugs" of things like, all results being hidden when searching for democrats and LGBT, and people being set to follow trump.