Don’t lose potential fans
People have liked your post let’s say. Does that mean they follow you, no. Here is what you want to do. If you see that your post has gotten a reaction, like love, etc, then you click on it highlighted in blue, and you will see the people who liked your post to invite them into your fan page. You can also do this in your notification tab too. The reason you want to do this is so that when you post new content, they will be able to see your posts on their timeline if they liked your page, not just a post.