For comparison Twitter has 586 million MAUs. So Bluesky is at 3% assuming all those are active. In terms of HN posts over the last 3 days (excluding posts about itself) it's 47-2 in favor of Twitter. Which sounds bad but it's a whole lot better than the ghost town that is Threads which has 0 and way more "users." So definitely on a better than the last "Twitter killer" but I'm still not betting on it.
Threads never had a chance. No one wanted to hand Meta another community to exploit. I think the big difference this time is I am seeing a critical mass of big accounts start to shift with Major News Orgs, Kelsey Hightower, Emily Freeman, Steven King and others exiting Twitter. Tech BlueSky is starting to look a lot like what Tech Twitter used to pre-Leon. Content is king and content is moving.