Because if they show you: Ads > Friend's image/text > Group image/text > Pages I like image/text > Friends of Friends image/text > Memes Then you'll go throug

Because if they show you: Ads > Friend's image/text > Group image/text > Pages I like image/text > Friends of Friends image/text > Memes Then you'll go through a few and then leave the site. Ads > Friend's image/text > Group image/text > Leave FB They optimize how much time you spend on FB, so they can show you more ads. Thus, it makes sense to stick the stuff you really care about at the end. To make it hard to find. Because, then instead of coming to the site and getting what you want, you'll spend an hour trying to dig through the crap to find what you want. More "engagement" is more ads. Nobody at facebook through about whether it makes sense to measure "engagement" alone, or to try and measure some form of "valuable engagement", or "useful engagement".