it's SEO, plain and simple. Facebook doesn't show you everything all of your friends say, it uses 'edge rank' - a complex algorithm - to choose what gets shown

it's SEO, plain and simple. Facebook doesn't show you everything all of your friends say, it uses 'edge rank' - a complex algorithm - to choose what gets shown and what gets hidden. There is much speculation around what the actual inputs are, but no doubt that likes are taken into account. So, someone who posted something with 1 million likes is more likely to have a better edge rank and you're more likely to see things from them in the future.