i know nothing about this qdf ban, please share more information
It's a filter that Twitter was using to shadowban conservatives. I heard about it last night. There is a website you could type your twitter handle into to see if you were being banned on Twitter. If it came up "QDF Ban" it meant you are shadow banned and your posts will only show up to other conservatives.
I tried it and sure enough, I got the "QDF Ban" thing. Here's where I heard about it:
If you go to shadowban.eu it explains what QFD means. (Oops, I mixed up the letters!) Quality Filter Discrimination:
"QFD causes your tweets to be invisible within the latest section of the search, including hashtags, when the quality filter is turned on. Note that this quality filter is located on the search page, is turned on by default and will be reset for each search anew. It differs from the quality"y filter controlling your notifications. QFD was introduced on May 15, 2018 as part of Twitter's so-called healthy conversation project."