Bullshit. There was never this "understanding", just an assumption by people who were too blinded by greed to do a little simple math. There is only so much attention to go around and only so many items that can be put into a persons feed before it loses any value to that person. You were only able to communicate freely to this audience because there were so few using the channel. Once it was shown to actually be effective you were competing with everyone else for that small slice of attention. Welcome to the market pal, hope you brought your wallet! If a marketer complains because everything they post each day isn't pinned to the top of people's news feeds for free then it seems to me that FB is doing it's job. I would much rather have my feed curated for things that are relevant for me than for every piece of marketing some store I once liked four years ago wants to send me.