Gnus for Mail and Newsgroups
Gnus does not ever delete e-mail messages unless you instruct it to. To delete a message use Backend -> Delete from the Article menu.
This way of individually deleting messages, however, can get cumbersome. So this is a good time to learn about marks. Marks allow multiple selection. In the Summary buffer you can mark a message using the # key. A # appears to the left of the message header to indicate that this message has been marked.
Once you have marked a bunch of messages, any command you try will apply to all of them. For example, mark some messages with the # in the article buffer, and then select Backend -> Delete article. You will be asked to confirm that you want all of these e-mails deleted forever.
Some groups should be deleted automatically. Your spam group is a good candidate. You want to keep messages in there for a little while (so that you can make sure occasionally that nothing important ended up there), but you don't want hundreds of messages about Viagra and pyramid schemes to be cluttering up your hard drive. Gnus allows you to specify that some groups should be automatically deleted. Insert the following into your .gnus file:
(setq gnus-auto-expirable-newsgroups "mail.spam\\|mail.cygwin")
This will cause articles to be expired in the spam group and the Cygwin mailing list group. Expired means that about a week after you get them, they'll be deleted. Put as many mail groups as you like in this line, separating them with \\|.
Gnus also can help you decide which messages to read first. For example, if one author's news postings are always worth reading, you can ask Gnus to rate those articles higher than others so they are brought to your attention. This process is known as scoring. If you want to see more of something, increase its score. If you want to see less of it, lower the score.
It's helpful to score your own posts highly; that way you can easily find them. First select Post an article from the Post menu. If you do this while reading a group, you automatically will be posting to that group. If you are not reading a group, you must enter the name of a group at the top of your post.
When you've finished typing a message, select Send message from the Message menu. Give it a few minutes, then refresh Gnus by selecting Check for new news from the Misc menu. To set up scoring, find your posting. While reading it, select Increase score from the Score menu, which present you with a number of choices. Use the ? to see your choices. Then press the A key, which tells Gnus you are adjusting the score for the author. You are then offered another set of choices, select S. For your final choice, select P; your name and e-mail should appear. Now press the return key. You have just increased your score, and your posts will appear in bold face type.
So many groups, so little space on the screen! There is a way to create groups of groups, which can help organize your mail and news even further. These groups of groups are called topics. Select Toggle topics from the Misc menu. Put the cursor at the top of the screen and select Topics -> Create from the Topics menu. Enter the name of a topic, and a new (empty) topic will be created. To move a group into that topic, put the cursor on the group name, and select Groups -> Move from the Topic menu.
Play with these groups and groups of groups for a while; you'll find them a helpful way to further organize your mail and news.
Gnus has so many options and features that it can seem quite intimidating. The reason to use Gnus is it is a news and mail client you will never outgrow. Using group selection methods, you have apply sophisticated sorting to incoming e-mail. With scoring, Gnus can become an intelligent partner in your on-line existence.
A wealth of information about Gnus and Emacs is available for free on the Web.
Windows users should also look at the GNU Emacs FAQ for Windows 95/98/ME/NT/XP and 2000.
The Emacs manual is included in the Emacs distribution and can be found in Emacs by typing M-x info. If you want it in HTML, ASCII or some other formats, look here.
Once you get Gnus up and running, you can post questions to the gnu.emacs.gnus newsgroup.