3.1. From Email
You can use a feed to display all your announcement-only mailing lists; you can also use it as a disposable email address when you register with web sites and the like. This frees your inbox and protects your real email address from being sold to spammers.
There are two services that do this, and both are very reliable: MailBucket (http://www.mailbucket.org/) and Dodgeit (http://www.dodgeit.com/).
Both operate in the same way. You send mail to firstname.lastname@example.org or email@example.com, where xxx is your own chosen identity. There's no sign up, so you need to check that your chosen identity isn't already taken. This highlights one issue: your mail isn't private, so don't use it for things you don't want others to see. (You could use an incredibly unguessable identity to make such risks very unlikely.)
Once the mail starts to arrive into your inbox, it will look like Figure 3-1.
Figure 3-1. The Dodgeit.com inbox on the Web
You can then subscribe to the feed at either http://www.mailbucket.org/xxx.xml or http://www.dodgeit.com/run/rss?mailbox=xxx. You will then see something like Figure 3-2 in your reader application.
Figure 3-2. The Dodgeit.com inbox inside NetNewsWire
Personally speaking, I think these services are the cat's pajamas. There are many mailing lists that don't require the ability to reply, or to which you might not actually want to contribute, or whose traffic is so great, you might not want your email application to keep firing off new mail alerts. These services are perfect for that.
Gmail, Google's beta email product, also produces a feed of your inbox, but because it's in beta, it's hard to say if the feed will still be there by the time you read this.