In addition to what is written on the home page, there are some things you might want to know:

Kind of e-mails we accept
Any kind at the moment, but we might limit some notable spammers.
Size limitation
We will not take e-mails longer than 1MB in size, attachments included.
Attachments
We receive them, but no downloading is available - we are still working on it.
Composing e-mails
Use the "send e-mail" link from the main menu, but you have to prove you are human and type some crazy characters into a text box when prompted. On a positive side, we don't ask you to dance.
Replying to e-mails
Use the reply link on the page that shows your e-mail's text. Humanity is still enforced, though.
Sending carbon and blind copies
Not currently, but we are actively debating if it's a useful feature. Drop us a line at support if you think you want it.
Keeping e-mails longer
Absolutely: every time you hit the "keep" link, the storage time will be extended by a week. So, you can keep some messages forever if you remember to extend them once a week.
Deleting an account
You can do this, but remember, that the account did not exist in the first place: it was created when an e-mail message arrived for it. You can delete the account by deleting all messages in it. It will resurrect if someone will send a message for it, though.
Renaming an account
Simple - just think up some new name for your account and stop using the old one. All the messages in the old one will eventually expire and the account will be removed.
Advertising
We accept image or text ads that fit into a rectangle of 160x600 pixels. Send your inquiry here.
Investment opportunity with this service
We will gladly take you money. Provide your contact information here.
Other limitations
At some times we might need to throttle the storage and network bandwidth. It means that we might keep fewer of your e-mails and keep them for shorter time periods. We usually put out announcements on the front page when that happens.