If you are into RSS, have a look at MailBucket.org. Send emails to any address at mailbucket.org (say: gaga@mailbucket.org), and view the messages sent to that address as an RSS feed (http://www.mailbucket.org/gaga.xml).
You want a temporary email address to register on some site? You want to get news about a project or a company, but they do not have an RSS feed and can only send you updates by email? Then Mailbucket.org is the solution for you. Thanks Tom for this great service!