RSS (Really Simple Syndication) is a set of standards for feeds and site updates utilizing a single XML feed file. RSS files contain various entries, where each new entry is normally post on a blog, video, streaming site. This file is hosted statically on the publishers website and can be read by users.
In order to actually read RSS entries and enjoy consuming the best way possible, you need an RSS reader. Here is a somewhat comprehensive list of some common readers.
This is a great program covered really well in this article.
Sfeed is a parser for RSS that can be used to make a client. Their website covers all recources on how to use it.
Newsboat is the the titular terminal-based RSS reader; It can be extensively configured to handle feeds in many creative different ways, such as downloading and playing YouTube videos with youtube-dl among other things.