I use "feed" to refer to a neverending stream of media where the newest content shows up first. This is in contrast to an "archive" where newer media receives no special treatment.
Feeds tend to be unenlightening because of the Lindy Effect. Suppose a feed shows the last month of content. Then according to the Lindy Effect, the educational benefit of keeping up with the feed will plateau after one month of consumption and disappear after one month of abstinance. Keeping up with a feed provides no long-term intellectual benefit.
The worst thing about feeds is they impair your agency.
An archive is accessed via a search tool. You start with a question and then use the archive's search tool to discover the answer. This is a self-directed process. If you have no question then you do not access the archive.
A feed often feels like a machine that answers the question "What is new?" But there is too much incoming information for a feed to show everything new to you. Feeds must curate content i.e. feeds decide for you what is important.
Letting someone else—human or machine—decide for you what is important equals abnegating agency. People attached to media feeds tend to be sheepy compared to readers of non-volatile media like books. Neither is it a coincidence the worst negative effects in my Mediums Overpower Messages post come from media feeds.
Endless media feed aggregators produce the worst effects. Individual blogs and webcomics[1] produce no worse than a small negative effect because individual creators cannot create enough content to thoroughly displace independent thought.
A media feed can become a feed or an archive depending on how you use it. The YouTube homepage and sidebar recommendations are feeds; the YouTube search bar is an archive. Reddit's "hot" posts is a feed; its "top" posts "of all time" is an archive. The Facebook news feed is a feed; an individual Facebook user's photo collection is an archive.
There are many ways of turning feeds into archives. Downloading YouTube videos with youtube-dl helps me watch video cogently. Accessing Facebook via https://facebook.com/messages helps me evade its news feed.
[1] Following other creators makes my work derivative. I am giving up blogs and webcomics not because of the Lindy Effect but because I am creating my own blog and webcomic instead. ↩