Tumbleweed Communications and Mitsui & Co Sign Partnership Agreement

REDWOOD CITY, CA - May 10, 2000 - Tumbleweed® Communications Corp. (Nasdaq:TMWD), a leading provider of secure Internet communications services, today announced the appointment of trading company Mitsui & Co as its business partner in Japan.

"We are delighted to have Mitsui & Co as our new partner," said Jeffrey C. Smith, chairman, president and CEO of Tumbleweed Communications Corp. "We see this partnership as an important step toward establishing our Integrated Messaging Exchange platform as the standard for online business communications in Japan. The Japanese market for secure online communications systems continues to grow, particularly in vertical markets such as finance and government. We are confident that the support of Mitsui & Co will help Tumbleweed IME penetrate the critical markets in Japan."

"Tumbleweed Communications provides a secure, open standards-based, messaging delivery infrastructure for the Internet," says Yoshifumi Fukushige, Management System Department general manager in Mitsui & Co's IT Planning and Administration Division. "IME satisfies the needs of companies as a messaging solution for the financial market and postal services.

"Tumbleweed is expanding its business, not only in the area of system development but also as a messaging solution provider. Mitsui welcomes this opportunity to support Tumbleweed's endeavours and to be a multi-business partner," Mr. Fukushige adds.

In recent years Mitsui & Co has been successfully diversifying into service and information-related businesses. Mitsui chose to partner with Tumbleweed based on the strength of Tumbleweed's patents, the superiority of the Tumbleweed Integrated Messaging Exchange™ (IME™) platform, and the business model.

Mitsui & Co., Ltd., one of Japan's largest general trading firms, is chiefly involved in the import and export of commodities including steel, non-ferrous metals, machinery, chemicals, textiles, food stuffs and general merchandise. For its 1999 business year the company generated gross sales of %11,799,903 million ($107,271.84 million) and a recurring profit of %59,583 million ($541.66 million) [exchange rate Y110 = $1].

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.