Also it should be noted that many of those "more than 7 note" scales such as the Blues/Mixo-Blues scales (there are tons of these in jazz) the composer/musician can view them in multiple modal states because of the extra notes. This allows for extra chords in between chords and flopping around between the modes those scales are built off of.
 
This allows one to break modal/key rules while not having to worry about the key/modulation as much. You just accept the "accidentals" as being inherently "there" and build your harmony/melodies and write your sheet music based on that. That's what allows for those crazy chromatic chord progressions and the scales the conjure up and/or create.
 
That's kind of what Kamikaze seemed to be getting at but I brought it up earlier in regards to the Mixo-Blues scale being a combo of Mixolydian and Dorian with an extra diminished 5th (or it could be viewed as an augmented 4th) step. That's really advanced stuff that should only really start being analyzed after really nailing the fundamentals of key/mode/interval/chord theory.
 
I attempted a proper old school jazz study a couple years back and I "got it" but gatdagned those nerds are over the top. The extra notes (and then the rules applied to them over the years) just blow things up to a much more complex overall pattern. Without the fundamentals it really just turns into gibberish very quickly and the only other option is to learn tunes by rote... which is restricting and a pain in the ballz.