Circle is starting to roll out to more users now that it has been tested with a limited group. The feature allows users to send out a message to a group of people rather than all of them.
You can check if you have access to the circle by updating your app or using a web browser. You will see a menu at the top that reads Everyone when you start writing a message. You can choose to limit your account to a specific group or you can add or remove people from it. If you add or remove them, you won't be notified.
If they follow you or not, you can add up to 150 users to your Circle. Users in your Circle will see a note appended to Circle-only tweet, stating that only people in your account can see it.
The people in your circle won't be able to see everything you post, but they can still download and suck it up. Even if you're sending a small message to a smaller audience, the community guidelines still apply.
Although it seems like more users are getting access to the feature, it is still in testing.
It's not clear how many people have access to Circle. It looks like more users are finally seeing the feature pop up when they start using it, but some users still don't have access yet.
There is a statement from a Twitter spokesman, as well as to reflect that Circle hasn't been rolled out to everyone yet.