These are generally the rules we go by when creating lessons:

Difficulty Explained

Absolute Beginner: for someone who can't play guitar at all, doesn't know what a fret is.
Beginner: for someone who knows what a chord is, but still can't play guitar at all.
Easy: for someone who can play basic chords and smoke on the water.
Intermediate: for someone who is familiar with all chords, and can play simple leads.
Advanced: difficult to play or difficult to understand.
Extreme: very difficult to play, unless you practice several hours per day.


Focus/Category Explained

Artist: lesson focused on how to play like a particular guitarist
Chords: lesson focused on chords.
Exercises: no one so far is confused by this.
Jam: only use this if you have a jam background track in the lesson.
Reference: explaining things that are not scales or theory.
Rhythm: lesson explaining rhythm guitar, rhythm theory, drum machine programming.
Scales: scales and modes go here.
Song: lesson explains how to play a particular song.
Sound Effects: how to make your guitar sound like a whale or siren or....
Studio: how to set up a studio, or use non-guitar equipment.
Style Tutorial: how to play a particular style.
Technique: how to slide, tap, roll, etc...
Theory: music theory only.
Tricks: lead riffs, things that defy categorization, here's a thing I made up.