A while back I had read on either Dose of Digital or JohnHaydon.com about the fact that Facebook is set to automatically show ONLY posts from people who you’ve recently interacted with or interacted the most with. This is the reason why you may only be noticing that “some people haven’t updated their status on Facebook in a while” (or some pages you thought you were following are not posting any updates). They are, you are just not seeing them.
Though, this means that you will see MORE updates on your Facebook home page (and that means you may end up wasting more time on Facebook than you do now), if you want to change this, this is what you need to do:
(Thanks to this Facebook event for reminding me of this…)