big, messy

lots of global variables

"The nnfolder directory" nnfolder-directory (used by
e.g. nnfolder-generate-active-file) -- huh? Should be per server.

e.g.
(let ((nnfolder-directory "~/Mail/archive/archive"))
  (nnfolder-generate-active-file))

creates the active file for the "first" nnfolder server (don't know
the exact criteria, but it's always the same server, no matter what
the value of nnfolder-directory is)


-----

No clean separation of components. E.g. the "nnml" backend appears to
do lots of thigs that a backend isn't supposed to do. From the manual:

| Getting Started Reading Mail
| ----------------------------
| 
|    It's quite easy to use Gnus to read your new mail.  You just plonk
| the mail backend of your choice into `gnus-secondary-select-methods',
| and things will happen automatically.
| 
|    For instance, if you want to use `nnml' (which is a "one file per
| mail" backend), you could put the following in your `.gnus' file:
| 
|      (setq gnus-secondary-select-methods
|            '((nnml "private")))
| 
|    Now, the next time you start Gnus, this backend will be queried for
| new articles, and it will move all the messages in your spool file to
| its directory, which is `~/Mail/' by default.  The new group that will
| be created (`mail.misc') will be subscribed, and you can read it like
| any other group.
|