Simply put the Facebook newsfeed ranking algorithm (or Edgerank) is…
The more users interacts with a page the more likely they are to see a new post from that page. If there’s little interaction they are less likely to see it.

What does ΣUeWeDe mean? AFFINITY ( U ) — This rates the interaction between the user and the poster. The more the user interacts with this poster the more likely they are to see it. This is how connected a particular user is to the edge being posted. These connections are made by looking at specific actions. Actions include:

Clicking
Liking
Commenting
Tagging
Sharing
Friending
Clicking “see more” – Very important 

WEIGHT (W ) — Different post types carry different weight. In order.

1,Photos/Video
2.Links
3.Plain text posts

TIP: Use new Facebook features. Facebooks assigns a higher weight for new features to encorage usage.

Engagement from other users effects weight , so a text post can weigh more than a photo post if it has more interaction .

TIME DECAY ( D ) — As a post ages it loses value. This also depends on how often a user logs into Facebook. There’s still a chance user who don’t log in for a week will still see your post.

HACKING YOUR PAGE If you want more interaction on you page you have to post micro content that people engage with. You must understand that people don’t want to be sold to all the time.

If you post buy our products and you’re not getting any interaction you’re slowly killing your page. Less and less people will see your future content.
(This is why buying fake Facebook fans is so damaging)

THE CONTENT The idea is to drip feed micro content that’s super engaging( this doesn’t has to necessarily tied to you brand)… Then when you do post about your product it will reach more people.

Your micro content can be on text posts on current affairs or interesting quotes or images(whatever, as long as it gets likes/shares/comments).

Social media marketing “experts” suggest promoting posts to reach a larger audience. (Surely most marketers know spending money will extend their reach? Not really any insight.)

Facebook will stop showing your advert if it’s not getting engagement, and charge you more.

So it makes sense to promote not only your main sales content but your micro engaging content too.

Owning a house on rented ground. Finally building your page on Facebook is great, but you must understand you’re building a house on rented ground. Only recently Facebook updated the algorithm and less of your fans are seeing your  content. (3 out of every 100 on average)

So don’t put all your eggs in one Facebook.