Regarding Benoit's Jam Track located here: http://www.guitartricks.com/lesson.php?input=8577

Originally Posted by: Kurgan1536He uses a I iii I iii V vii iii V vii iii progression.[/quote]
That assumes C is the root-tonic. However, you could (and should) look at other possible roots. For example, if you consider all the notes that are contained in all the chords:

C major: c-e-g
E minor: e-g-b
G major: g-b-d
B minor: b-d-f#

Then write them alphabetically (as if in a scale or mode):

c-d-e-f#-g-b-c

Then identify the intervals in between the notes:

c (WS) d (WS) e (WS) f# (HS) g (2WS) b (HS) c

You can discover that what you have here is C Lydian mode (without the "a" note as the major 6th). Makes sense?

Alternately, you can look at the notes comprising the chords and identify a key signature based on the presence of sharps/flats. Only one accidental present in that collection: f#. Therefore, what you have are chords that are in the key of G major (or E minor, the relative minor of G major).

So, look at the modes of G major:
G ionian
A dorian
B phrygian
C lydian
D mixolydian
E aeolian
F# locrian

Conveniently enough :p we find that C lydian is one of the modes of the key of G major.
[QUOTE=Kurgan1536]I wonder which mode you would select to play in and why.

That depends upon what sound you intend to create. You could for example play in E Phrygian over the C major, E minor and G major chords. This is a good way of looking at the chords, too. Mostly because, then you have a tonic-dominant happening: C(I)-G(V). Then switch to something else when the B minor chord happens, perhaps B aeolian, or any mode that contains the note of a B minor chord (b-d-f#). For example, G major as noted above.

You could also just play right through the B minor chord staying in E phygian if that is the sound you want to create. But notice that E phyrgian has an "f" as it's second note and this will clash with the "f-sharp" of the B minor chord. But if you desire that dissonance, then of course, include it (the f-sharp appearance is actually rather brief).

The point here is to have a system for dealing with identifying, understanding and applying the ideas so you can achieve your intended result.

Or in other words, "Yeah, I think you are on the right track." :) Hope this helps.