Facebook has upgraded it’s iPhone app to enable users to have better control over what they see in their newsfeed.
The ultimate goal of the newsfeed is to show you the most relevant information to you so you keep coming back to Facebook. Facebook does this via algorithms that pick up what show interest in.
iPhone users will initially get the update, which will allow people to select who is seen first in their newsfeed, which people you do not want to see in your newsfeed and which pages you want to see less or more of.
Source: Facebook Newsroom