As new users downloaded the app, Bluesky jumped to becoming the app to No. 1 in Brazil over the weekend, ahead of Meta's X competitor, Instagram Threads.
If I have mastodon, how and when can I follow Blue sky users? I read something about an adapter server or something, but I don't know what that means in a practical sense.
There is Bridgy Fed, which bridges accounts over to the other side if they follow the respective Bridgy Fed account on their platform. This is opt-Ăn though, so you can't just follow anyone, they need to have followed @ap.brid.gy on Bluesky. To have your interactions bridged you need to follow @bsky.brid.gy@bsky.brid.gy.
If the account you want to follow is not bridged and you are okay with just reading their posts, you can also use a service like RSS Parrot as every Bluesky account also serves as an RSS feed.
Just an FYI for the RSS thing: if a Bluesky account is set to be viewable to logged-in users only, its RSS feed will not work. It only works if the profile is viewable publicly without logging in.