The platform crossed the milestone last night, and it happened about a month and a half after the 25 million mark. Bluesky still has a long way to go to pass Threads, though; Meta’s platform has more than 100 million daily active users.
[Media: https://bsky.app/profile/bsky.app/post/3lgu4lg6j2k2v]
Roughly 10 million.
I would consider 1/3 a notable contender. Granted, only ~1 million of those users are active daily, but that’s still very significant for a FOSS alternative.
EDIT: Source