U = Affinity, Affinity between the user who posted (that is you) and the user that will read it (your audience).

Affinity means a close connection marked by community of interests or similarity in nature or character, in other words, relationship between poster and audience. Affinity score can be different for different users, for example, if one of your follower, let’s call it user "a" interact with the poster's post, then Affinity score will be high for "a" in compare to a user "b" who interact less with your post, hence your post will not be in top news for "b". Therefore, social media manager need to involve as many fans as he could. To control affinity ratio can be quite a trick part especially for small businesses.

Factor W:-

W = weight-age of your post.

There are no particular set of rules which could decide the weight-age. Though, usage of media related content (like pictures, video and links) are considered as "heaviest" type of post and it can be quite decisive factors. Hence, next time while updating your important status message, try to use media related content within it. Another factor affects post weight is engagement ratio on that particular post, if you receive x number of likes and comments in post, the heavier it is. One way to improve weight-age of you post is to deliver right content to your users, else you can press them by asking their opinion or answer about stuff.

Factor D:-

Comparatively with other factors, D is much simpler factor and requires no extra fibers to digest it.

D = recency of the post.

The fresher the post, the better it will be flow in the top new section. Older post (more than 24 hours or so) will rarely make to the top, unless and until they have strong influence. Best way to overcome this situation is to post on regular basis, with fresh and unique content.