From a message posted on their site:

Dear Basejet Customers and Users,

It is with a heavy heart that we must report to you that the Basejet service is being discontinued. We have spent the last three years building a business around providing a premier wireless email solution for smartphones. However, in spite of much hard work and sacrifice by our dedicated team, and the enthusiastic support of our users, we have been unable to raise the additional funds necessary to maintain the business with the right level of service and support. We have, however, decided to use the remaining funds to cover the hosting fees for the Basejet service for another six months (through January 2005).

We'd like to thank all of the users who have enjoyed this product over the years. You can continue to use the service through January of 2005, or start looking into some of the other solutions available today.

http://www.palmone.com/us/wireless/email/compatibility.html

Again, we thank you for your support.

- Basejet Team

Basejet was a full featured email client, as shown on our Fact Sheet for Basejet. On the server side it supported Microsoft Exchange/Outlook, Lotus Domino/Notes, and push POP3/IMAP. On the Treo side it could pull any POP3 or any IMAP mail service. It had HTML and attachment support. It also is one of the only email clients to support MAPI, the protocol that hotmail uses. Basejet offered great competition; it is sad to see a powerful email service for the Treo die.