After finishing my first major mode for use at work, I took a stab at writing a minor mode for a SomaFM mode I forked and modded. I’m new to writing code like this but happily, after some effort, I got that minor mode working. It simply polls the somafm-mode favorites file (songs favorited while listening to SomaFM in Emacs) and parses them to an Org file. It’s very simple and there’s much to do, but I instantly saw the possibilities.
This is actually a question to the community about the basic concept of polling data created by an Emacs major mode with a minor mode running in the background. I suspect it’s very common but as I’m just dipping my toes into coding modes, I’m seeing most of the ones I use every day from the outside; they do useful things and I’ve not peeked under the hood (outside code syntax-related ones) to see if this feature is behind any of that useful stuff.
What Emacs major modes utilize a listener that polls data files and then grabs the data for use elsewhere? Is that model a sensible one, in terms of a process actively running in the background in Emacs and “doing things”? It makes sense to me, as GNU/Linux is full of daemons “doing things” in the background, often supporting major applications that accept data from those processes. I just never thought about the model in context of Emacs before.
I realize I’m raising my newbie flag pretty high with this question, but I’m also really excited to write more modes. My first instinct is to be sure I “do it right” now that I’ve stumbled my way into writing something that actually works 
TIA