They will see everything of yours that they already can. It really doesn't affect anything that they see. But you won't see any of their posts, or any quotes of their posts. You also won't receive private messages from them. But it's still not all 100% hidden. Like if they do post in a thread, you'll just see a link at the bottom of the thread that says "Show ignored content." Then when you click that it will show the posts of the people that you have on ignore.
They will see everything of yours that they already can. It really doesn't affect anything that they see. But you won't see any of their posts, or any quotes of their posts. You also won't receive private messages from them. But it's still not all 100% hidden. Like if they do post in a thread, you'll just see a link at the bottom of the thread that says "Show ignored content." Then when you click that it will show the posts of the people that you have on ignore.