I have a Facebook page or two. I know how to read. I'm sure most people online can say the same. So why are people making this more complicated than it needs to be?
When you promote a post, it will be shown in the news feeds of more of the people who like your Page than you would reach normally. Friends of the people who have interacted with your post will also be more likely to see the story in their news feeds for up to 3 days from when the post was first created.Now, is that not simple enough for you?
When you use the "promote" feature, your post will be shown in the feeds of more people who like you page rather than how the new feed works based on contact. In addition, the friends of people who have interacted (liked, commented, shares) with your page are also more likely to see the promoted post for up to three days from creation.
If you still don't get it, here's the thing: You're paying for your post to appear in the feeds of people who don't even like your page.
The promotion feature allows you to target people that are more likely to "Like" your page based on friends. It is an ad, whether they like it or not.
I've personally seen these in my feed on a daily basis and they are all from the same page with the same friend. Apparently that page promotes a lot and that friend likes a lot of the things they post. Does that mean I like it? No, but they're trying to get people to view it based on your friends, just like a related post.
When a link is from a page you don't follow but has a friends' name attached to it, you're more likely to trust it and click. More than likely, it's totally worth the money for that factor alone, but if you have a lot of followers that are really engaged, that's promoting itself.
So, no, it's not something you have to do. It's not even something that people are advising pages to do, but it's a button and people are getting confused by it. Facebook is not forcing anyone to pay money to get their posts seen by their members. If they aren't engaged and don't interact with your page then they aren't going to get your posts, but it's the same way with friends and family so please don't throw a fit about it.
It's Facebook people--not your website. If you want to complain about it, don't use it! ..I think that's what happened to MySpace! Hehe.