Yes, this forum doesn't seem to get too much traffic, compared to some. It's a real shame. When you look at the name of it, it would seem to be a natural to get lots of traffic. But for some reason, it is in it's own separate forum section and then at the bottom of a long list of language specific ones.
All the various parts of PoodLL are great for doing the type of lessons needed for teaching/learning guitar. There are also some others you might want to consider also. For instance, if you want your students to be able to see and hear each others performances, you might want to use the Podcast activity. Submissions can be audio or video and can be set to allow students to see each others efforts. You can also set up the same type of activity by using the PoodLL datafield type for the database activity.
Another possibility, if you want to be able to do live face-to-face lessons is the WebRTC Experiments addon activity. It allows for two way video, audio, data, screen sharing, etc. I am in the process of trying it out myself as it works peer-to-peer without the dependency on a "central server" or a "streaming server".
Another possibility, but it takes a little doing to get it setup and working, is the Language Lab. It too uses both audio or video and can be set up in a series of lessons that students go through at their own pace with the ability to make multiple recordings for comparison until they get it right.
Oops, bell rang. Gotta do some work.