I found this thread while wondering the same question. The information is used by wordpress so you can make posts to your blog via email. The wordpress configuration page for this is at: Option->Writing
The configuration section is described as:
“Writing by e-mail
To post to WordPress by e-mail you must set up a secret e-mail account with POP3 access. Any mail received at this address will be posted, so it’s a good idea to keep this address very secret. Here are three random strings you could use:”
