p.s. CW = Content Warning, where the content of a post is hidden underneath a descriptive warning that you can click on to reveal the post.
This can be used for anything where people might be interested but they might not want to read it right now, for example something controversial or stressful or something spoiler-filled. Different people have different ideas of when their use is appropriate.
You can set CWs to always open automatically in your settings if you don't like seeing them.