Select methods versus Server buffer

[Mark Plaksin <happy@mcplaksin.org>]

What is the difference between setting the select-method variables and
using the Server and Group buffers to get news and mail?  Is there a
difference?  What's the relationship between the those variables and
the server information stored with each group in .newsrc.eld?

Everything seems to work fine with the select-method variables set to
nil.  I add servers via the Server buffer and subscribe to groups there
or in the Group buffer.

This worked well for me until just recently.  I added a second nnimap
server, some nnrss groups, and a bunch of nntp groups at gmane.org.
Now when I '5 g' in the Group buffer, it doesn't always check all the
groups.  It doesn't check *any* nntp groups until I M-g on each group
or on a topic containing the groups.  I don't know that this is caused
by my nil select-method variables but I've always doubted that they should
be nil :)

Also, can somebody explain the relationship between the properties of a
server in the Server buffer and what gets saved into .newsrc.eld?
Before I looked at .newsrc.eld, I thought that server information
(i.e., the name and properties like nnimap-address) was stored in a
server section.  And each group had a pointer to the name of the server
it came from.  If a group had parameters intended to override the
servers settings, they were stored with the group too.

But it seems more like all of the server information is stored with each
group in .newsrc.eld and the server buffer is the list of unique servers
that show up in groups defined in .newsrc.eld.

Thanks for any insight!