On Netarhia, each author has his/her own personal RSS flux, containing only his/her writings. Just an extra-feature for better exposure, does not require any tweaking or particular attention on your side.
It is the flux containing all writings on Netarhia, by all authors. Just the same, you need not worry about it, it's automatically generated.
RSS stands for Really Simple Syndication (as of RSS 2.0) and represents a way of presenting pure and standard format information from websites, optimized for easy access with variuos tools such as RSS readers, RSS aggregators etc. Essentially, it is a mean to standardize and simplify the presentation of information. If you got the time and are in an especially geeky mood, find out more about RSS.