Postal Service Offers PosteCS™

WASHINGTON - May 9, 2000 - The US Postal Service today launched Post Electronic Courier Service, PosteCS™, a global electronic document delivery service that enables users to securely send documents via the Internet.

Starting today, customers may log on to, follow the link to PosteCS, and register for a free 30 day trial service. The site also features a list of frequently asked questions (FAQs) on this new service offering.

"PosteCS brings the trust, security and peace of mind that the Postal Service brand is known for to the area of global electronic communications," said Deputy Postmaster General John Nolan. "In addition, through PosteCS, customers have the option of using the USPS Electronic PostmarkT which provides an added layer of security for electronic documents."

PosteCS offers increased security to the speed and convenience of electronic delivery for businesses and individuals who use the Internet. When a document is sent using PosteCS, it is available at a unique Web address (URL) created specifically for the secure delivery of the package. The recipient, who is notified in an email message, can then retrieve the document by clicking on the URL link which is given in the message and download the file.

PosteCS allows the sender to track:

• when a document arrives at its Web address,
• when the recipient has been notified of delivery, and
• when the recipient has actually opened the package.

The basic $1.70 fee for PosteCS includes the following standard features:

• delivery tracking,
• capability to import mail lists and
• set document expiration dates.

Customers may also add additional features including:

• encryption,
• password protection, and
• the USPS Electronic Postmark™.

The USPS Electronic Postmark™, introduced earlier under the Postal Secure Services™ family of services, adds an additional level of security by providing date and time stamping and tamper detection for electronic messages. PosteCS, a cooperative venture of the US Postal Service, La Poste of France, Canada Post Corporation, and the International Post Corporation (IPC), has been extensively pilot tested. Based on the success of the pilot, Canada Post Corporation commercially launched the service last month and La Poste will be launching soon.

PosteCS is built on Tumbleweed Communications Corp.'s Integrated Messaging Exchange™ (IME) which combines an advanced software platform and customized applications to establish a vital Internet communication channel between a business and its customers, suppliers, and partners.

"We are pleased to be working with the Postal Service on this initiative," said Jeffrey C. Smith, president and CEO of Tumbleweed Communications Corporation. "Through PosteCS, our messaging platform will allow businesses to quickly establish a valuable online communication channel that creates stronger relationships with their customers and partners."

The Postal Service's web site, which first appeared in 1994, has continued to change in response to the needs of Postal Service customers. In addition to the link to PosteCS, it now includes direct access to a number of electronic services including USPSeBillPayT, a new on-line bill presentment and payment service; Stamps-on-line, direct ordering and fulfillment of postage stamps and philatelic products; an interactive ZIP Code locator; and a great deal of information about hard-copy and package services.

About Tumbleweed Communications Corp.
Tumbleweed is a leading provider of solutions for managing secure communication and collaboration to enable the business Internet. Tumbleweed's robust policy-based framework empowers organizations to safely share and protect critical information, increase customer loyalty and privacy and dramatically reduce costs. Tumbleweed is trusted by 1,000 blue-chip customers including American Express, Chevron, Datek Online, the European Union's Joint Research Council, First Union Wachovia, John Deere, Merrill Lynch, Nike, Northern Trust, NTT, Salomon Smith Barney, Travelers and US Food and Drug Administration. One hundred of the Fortune 500 are Tumbleweed customers. Tumbleweed Communications was founded in 1993 and is headquartered in Redwood City, Calif., with offices around the world.

Except for the historical information contained herein, the matters discussed in this press release may constitute forward-looking statements that involve risks and uncertainties that could cause actual results to differ materially from those projected, particularly with respect to the security features of Tumbleweed's products and the activities of any third party. In some cases, forward-looking statements can be identified by terminology such as "may," "will," "should," "potential," "continue," "expects," "anticipates," "intends," "plans," "believes," "estimates," and similar expressions. For further cautions about the risks of investing in Tumbleweed, we refer you to the documents Tumbleweed files from time to time with the Securities and Exchange Commission, particularly Tumbleweed's Form 10-K filed March 30, 2001 and Form 10-Q filed November 13, 2001. Tumbleweed assumes no obligation to update information contained in this press release.