So a surprisingly large usability difference between Cohost and Weasyl is that Cohost shows you the five most popular tags containing what you've typed, in descending order; while Weasyl just leaves you alone. This means Cohost points you to the more popular #plush tag over the synonymous #plushie tag, while Weasyl leaves you to figure it out.
Cohost does still manage to have #plural and #plurality trade places every couple of days though, which is funny.