I've had a similar experience. Back in the days I used to have interesting talks with a bunch of people from overlapping networks, and met a lot of friends that way. Nowadays I'm just spammed by all the rubbish posted by people I shallowly know while the people I want to keep in touch with are invisible. It's been years since I've actually met somebody interesting on FB. They're actively obfuscating valuable content for their users to force-feed them with content that's valuable to themselves.