Posting
A post is a photo (or a video, with boopr+) that shows up in your friends' feeds. By default it goes to all of your friends, in the order you posted it. No captions written for an algorithm, no hashtags, no reach to optimize. Just something you wanted your friends to see.
Lists: posting to just some friends
Sometimes you don't want everyone to see a post. A list lets you group friends (close friends, family, the people who were on the trip) and share a post with only that group. Lists are made up of your friends, and only the people on the list will see the post.
Who saw it is locked in when you post
When you post to a list, boopr records exactly who it went to at that moment. If you rename or change that list later, it doesn't change who already saw the post. The post keeps showing the list's name from when you posted it, so you can remember who you shared it with. That label is just for you; tap it to see the current recipients.
Adding someone afterward
Changed your mind right after posting? You can share an existing post with another friend on its own, without deleting and reposting. They get added to that one post.
Lists are private to you. Your friends don't see which lists they're on, and the list name shown on a post is visible only to you. Lists are just a way to organize who sees what.