Most of the comments on here seem to be talking about whether the name is good or not. For me, the question isn't what a 'monoid' is called, or whether it can b

Most of the comments on here seem to be talking about whether the name is good or not. For me, the question isn't what a 'monoid' is called, or whether it can be defined in a few lines of English, but rather what it is that they are useful for. I've been using Scala full time for a couple of years now, but it took me ten months to really understand not just what monads are, but how they are useful in expressing a program from a different perspective to other approaches, and the benefits that come from that. Now I use them all the time and see how they add huge benefits to my code. In all the time that I've been working with Scala, and building my knowledge and experience of how to apply functional principles usefully, I have yet to (knowingly) use a Monoid, or encounter a situation where it was clear that they would have a benefit. I'm not saying that there are no such situations, and it may be that there have been situations where they would have been useful, but I didn't know it, and I would love to be able to add them to my toolbox. However, I do see that a lot of the time these concepts are introduced in a very abstract way and what it missing is not the simple definition, but rather some clear idea of when, how and why to use them.