Choosing Variables
------------------
Some variables relevant for moving and selecting articles:
`gnus-auto-extend-newsgroup'
All the movement commands will try to go to the previous (or next)
article, even if that article isn't displayed in the Summary
buffer if this variable is non-`nil'. Gnus will then fetch the
article from the server and display it in the article buffer.
`gnus-select-article-hook'
This hook is called whenever an article is selected. By default it
exposes any threads hidden under the selected article.
`gnus-mark-article-hook'
This hook is called whenever an article is selected. It is
intended to be used for marking articles as read. The default
value is `gnus-summary-mark-read-and-unread-as-read', and will
change the mark of almost any article you read to
`gnus-unread-mark'. The only articles not affected by this
function are ticked, dormant, and expirable articles. If you'd
instead like to just have unread articles marked as read, you can
use `gnus-summary-mark-unread-as-read' instead. It will leave
marks like `gnus-low-score-mark', `gnus-del-mark' (and so on)
alone.