One other modification to the algorithm they did last month is that they're cracking down on people using the wrong kinds of words.
I work(worked) for a tech news outlet and we share a lot of our news on Facebook. But since it's a lot about "Asus announces something" or "Samsung's new Galaxy something something" or "Major security flaw in Lenovo something or other", Facebook though these were commercials. That we were putting ads on the network and they weren't getting a cut of them. So they just blacklisted the entire site. The change was done without any sort of warning, and after we managed to get in touch with them, we were told that there will be further changes and none of them will ever have any warning.
So that's why Zon@IT couldn't post anything on Facebook for a month. Even now, they're watching for words related to brands to just gut the site.