Critical Path and 1stUp.com Team to Deliver Advanced Internet Messaging Solutions.

Business Editors/High-Tech Writers

SAN FRANCISCO--(BUSINESS WIRE)--March 17, 2000

Leading Provider Of Sponsor-Supported Access Joins Internet

Messaging Leader To Offer Solutions To Millions Of

Users Worldwide

Critical Path Inc. (Nasdaq:CPTH), the dominant global provider of business-to-business Internet messaging and collaboration solutions, today announced a multi-year agreement with 1stUp.com Corporation, a leading provider of sponsor-supported Internet access solutions and a majority-owned operating company of CMGI, Inc. According to the agreement, 1stUp.com will offer Critical Path's Web-based and POP3 (Post Office Protocol 3) email solutions.

As a value-added option to its affiliated free access partners, 1stUp.com is offering millions of users worldwide one of the most secure and reliable Internet messaging solutions available. As the brand-behind-the-brand, Critical Path enables 1stUp.com to provide customers with unlimited online usage as well as a comprehensive set of communication and collaboration solutions that can scale to meet the demands of millions of users.

"By providing Internet solutions that can be customized to reflect the branding and identity of any company, Critical Path and 1stUp.com are blazing a new trail in this fast-growing market," commented Charles Katz, president and CEO of 1stUp.com. "Critical Path's secure, reliable and scalable Internet messaging solutions offer another layer of value that we can offer our customers and enable us to differentiate ourselves from the competition."

"With partners such as AltaVista, StarMedia, SINA.com and Excite@Home 1stUp.com is a leader in the free Internet access space," said Doug Hickey, CEO of Critical Path. "The fact that 1stUp.com chose Critical Path to be its premier provider of Internet messaging solutions further validates our brand-behind-the-brand strategy and reflects Critical Path's ability to deliver industry leading communication and collaboration solutions that can scale to meet the demands of millions of users worldwide."

About 1stUp.com

1stUp.com, a majority-owned operating company of CMGI, Inc., is a leading provider of sponsor-supported Internet access solutions for consumer-oriented businesses. 1stUp.com provides patent-pending technology that enables its partners to brand, market and distribute leading edge, cost-effective Internet services to their customers.

The 1stUp.com solution enables consumers to receive unlimited, free Internet access in exchange for keeping a compact, sponsor-oriented navigation bar on their computer screen. Multiple leading ISPs support 1stUp.com's premium network, which delivers free, reliable Internet access to over 90 percent of the U.S. and Canada.

Aggregating the end-user bases of AltaVista, Excite@Home, Lycos, and sixty additional partners, 1stUp.com has the buying power of multiple brands and is able to pass along the benefits of optimal connectivity costs and advertising revenues to its partners.

Additional information is available on the company's Web site at: www.1stup.com. 1stUp.com Corporation is located at 88 Kearny Street, Suite 800, San Francisco, CA 94108. Telephone: [phone].

About Critical Path, Inc.

Critical Path, Inc. (Nasdaq:CPTH) is the dominant global provider of complete end-to-end Internet messaging and collaboration solutions for corporations, Internet service providers (ISPs), Web hosting companies and Web portals. Through its Allsourcing strategy, Critical Path is the only advanced messaging provider to offer businesses the flexibility to outsource, midsource or insource all or part of their messaging and collaboration applications.

Critical Path has built an industry-leading global infrastructure with data centers connected to key Internet exchange points and currently reaches more than 55 million end-users through its customer relationships. Critical Path provides reliable, secure and scalable e-mail and a flexible suite of enhanced messaging services to partners such as E*TRADE, CompuServe, Network Solutions, U S West, Sprint, France Telecom, British Telecommunications, and ICQ.

Critical Path is headquartered in San Francisco, with offices in locations nationwide and in Germany, England, Ireland, France, Denmark, Italy, Switzerland, and Argentina. More information on Critical Path can be found at www.cp.net.

This release contains forward-looking statements based on current expectations or beliefs, as well as a number of assumptions about future events, and these statements are subject to important factors and uncertainties that could cause actual results to differ materially from those described in the forward-looking statements. The forward-looking statements in this release address a variety of subjects including, for example, the expected benefits of the agreement between 1stUp and Critical Path and the expected functionality of the combination of the technology and products of 1stUp and Critical Path. The following factors, among others, could cause actual results to differ materially from those described in these forward-looking statements: 1stUp's products and technologies may not successfully interoperate with those of Critical Path; 1stUp's business model is dependent upon advertising and may be adversely affected by the adoption of new laws and regulations affecting the provision of Internet advertising services, including laws and regulations covering privacy, pricing and content; and increased competition and technological changes in the markets in which 1stUp competes. For a detailed discussion of these and other cautionary statements, please refer to CMGI's filings with the Securities and Exchange Commission, including CMGI's Annual Report on Form 10-K for the most recently ended fiscal year.

Note To Editors: Critical Path and the Critical Path logo are the trademarks of Critical Path, Inc. All other trademarks are the property of their holders.