After attracting 2 million users in its first year of operation, Bluesky has grown another 400 percent with some recent help from Brazil and Elon Musk. Are these monthly or daily users, or just account holders? Nobody knows! But it still has a way to go to match X’s estimated 250 million daily users and Threads’ 175 million monthly users.
Sorry I didn’t mean to sound cocky. It sounds like a byproduct of slow federation. As I edited my comment almost immediately (before you replied) after posting it, to correct said number and provide a source, but it doesn’t look like it got to your end.
Also MAU stands for monthly active users and not total users. But I realise that acronym may not be widespread.