becoming familiar with changes in Emacs, and then some

[sen_ml]

I was going through the changes since Emacs 20 last night and had the
following thoughts:

  1) Is there already a way for users to be introduced to the changes
     listed piecemeal over several different Emacs sessions?  For
     example, it seems like it would be pretty straightforward to have
     a `display-another-change' which could pick out a change and
     display it for the user.  Perhaps users would be able to mark a
     change as seen and understood so such marked changes would not be
     displayed upon further invocations.

     I learned about artist-mode (wow!) and was reminded about
     speedbar by going through the changes last night, but I confess
     that I don't find it easy to go through the list of changes on
     one or two sittings.

     It seems like such a mechanism could be helpful for other lists
     of changes -- well, at least for slow folk like myself who have
     trouble absorbing large amounts of material at once ;-)

  2) I noticed that M-TAB gets bound to `mail-abbrev-complete-alias'
     if `mailabbrev' is loaded.  It happens that I've bound M-TAB to
     switch focus (and raise) windows on the current 'desktop' of my
     window manager -- perhaps not unlike some other folks.  This lead
     me to think about whether there's an effort afoot somewhere to
     coordinate key sequences for use with window managers and for
     applications -- in particular to avoid key sequence collisions.

     Any such efforts already?  Or any interest in trying to do
     something about this?  I feel that customizing keybindings for
     the sake of working around these collisions is not a fun
     situation to be in at all.  Surely other people must be bothered
     by this too!