Metricom Secures $600 Million Investment from MCI WorldCom and Vulcan Ventures, Inc. to Fund National Wireless Data Network Expansion

Los Gatos, California - June 21, 1999 - Metricom, Inc. (NASDAQ:
MCOM), a leading provider of mobile data networking and technology,
today announced $600 million in funding from Vulcan Ventures, Inc. and
MCI WorldCom, each providing $300 million, to fund national rollout of
its Ricochet 128 kbps mobile data service. The first wave of commercial
availability is scheduled for mid-2000. In addition, MCI WorldCom and
Metricom have entered into a strategic relationship, which includes
national distribution of Ricochet.
Under the terms of the deal, MCI WorldCom and Vulcan Ventures, Inc.
will purchase 60 million new convertible preferred shares of Metricom
stock, priced at $10 per share. When consummated, and following an
allowed conversion from preferred to common, the breakdown of ownership
will include Vulcan Ventures, Inc. at 49 percent, MCI WorldCom at 38
percent, with the remaining 13 percent ownership held by other current
public shareholders. The transaction is subject to certain conditions,
including Metricom shareholder approval. Metricom will remain a
publicly traded company headed by CEO Timothy A. Dreisbach. The
investment underscores Vulcan Venture Inc.'s ongoing endorsement of
Metricom and the Ricochet technology.

Included in the strategic agreement, MCI WorldCom has signed a
five-year, non-exclusive wholesale agreement valued at $350 million
with Metricom for its Ricochet services. Metricom will utilize MCI
WorldCom's high-speed data and Internet network and support
operations as it expands nationally. Metricom will also enlist
additional distribution channels for Ricochet, and embark on a
multi-million dollar branding and marketing campaign to raise awareness
and advance adoption of the service among the target market of mobile
professionals.

"Our ultimate goal is to allow mobile professionals to take
their full desktop functionality anywhere they need to work," said
Dreisbach. "This means accessing data and applications on
corporate LANs and the Internet anywhere in the same fashion as sitting
in an office. By teaming with Vulcan Ventures, Inc. and a strategic
partner with the national presence and reputation of MCI WorldCom, we
gain the resources and expertise to accelerate the availability and
adoption of our Ricochet service on a nationwide basis."

Metricom targets multiple segments within the overall mobile worker
marketplace. One of these segments includes the mobile professional
"road warriors" who travel extensively for their jobs. In a
recent study, International Data Corporation (IDC) predicted by 2001
that 7.3 million of the professionals in this segment, who carry
cellular/PCS phones, laptops and other mobile computing devices, do
business within the metropolitan areas included on Metricom's
rollout plan. "The mobile professional market available to
Metricom is forecast to exceed 13 million users in 2005," said
Iain Gillott, vice president, Worldwide Consumer & Small Business
Telecommunications at IDC. "Critical success factors in this
segment of the mobile data market are the ability to provide cost
effective, reliable mobile Internet and LAN access throughout the major
metropolitan areas."

In addition to the primary business user market, Ricochet addresses
the high bandwidth data access requirements of residential users that
may not have viable ISDN, cable or DSL alternatives.

Unlike technologies just now evolving to solve growing
high-performance high-speed wireless data requirements, Ricochet is a
proven technology that leads the industry today at 28.8 kbps. Building
on Ricochet's success, Metricom has been testing 128 kbps service
and expects to launch the higher speed service in mid-2000 in the
following metropolitan areas: Atlanta, Baltimore, Chicago, Dallas,
Houston, Los Angeles, Phoenix, San Diego, San Francisco, Seattle, New
York, Washington, DC. Current rollout plans call for a total of 46
metropolitan areas to gain Ricochet coverage by mid-2001.

"We have been impressed with the management, focus, and
technology advancement made by Metricom over the past year," said
William D. Savoy, President, Vulcan Ventures, Inc. "By adding a
world-class partner like MCI WorldCom, we expect to accelerate the
availability and adoption of Ricochet by mobile professionals who want
fully functional access to applications and data on LANs, Intranets and
the Internet anywhere, anytime."

Ricochet is uniquely positioned to capture a significant share of
the growing mobile professional market with the fastest data speeds,
"always-on" connections, flat-rate
"all-you-can-use" pricing, no metered roaming fees, and true
mobility at 70 mph. These benefits are a result of the Ricochet
architecture, which is based on a digital packet-switched network
employing spread-spectrum radio frequency transmission and standard
Internet protocol (IP). Ricochet was designed from inception for packet
data, which means high throughput, extremely low Bit Error Rate (BER),
instantaneous handoff, and low cost per connection.

About Metricom Metricom, Inc. is a leading provider of mobile data
networking and technology. The Company's Ricochet service provides
mobile professionals with high-performance, cost-effective untethered
access to the Internet, private Intranets, local-area networks, e-mail,
and other online services. Ricochet is generally available in the
greater San Francisco Bay Area, Seattle, and Washington, D.C.
metropolitan areas; in select areas of New York City; on corporate
campuses; and at gate areas at major airports throughout the United
States. For more information, call 1-800 Go-Wireless, or visit
Metricom's Web site at http://www.metricom.com.

About MCI WorldCom MCI WorldCom is a global leader in communications
services with 1998 revenues of more than $30 billion and established
operations in over 65 countries encompassing the Americas, Europe and
the Asia-Pacific regions. MCI WorldCom is a premier provider of
facilities-based and fully integrated local, long distance,
international and Internet services. MCI WorldCom's global
networks, including its state-of-the-art pan-European network and
transoceanic cable systems, provide end-to-end high-capacity
connectivity to more than 40,000 buildings worldwide. MCI WorldCom is
traded on NASDAQ under WCOM. For more information on MCI WorldCom,
visit the World Wide Web at http://www.wcom.com.

About Vulcan Ventures Inc. Vulcan Ventures Inc. of Bellevue,
Washington was founded by Paul G. Allen in 1986 to research and
implement his investments. Allen's investments through Vulcan
Ventures, Inc.are long-term, as his goals enable him to take
above-average risks and a long-term view. Through Vulcan Ventures,
Allen invests in companies which offer products, services or
technologies that fit his wired world strategy, and can contribute to
or benefit from the technology and strategy of other Paul Allen
companies.

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Metricom and Ricochet are registered trademarks of Metricom, Inc.
All other trademarks are the property of their respective owners. This
press release may contain forward-looking statements. These
forward-looking statements are subject to risks and uncertainties.
Actual results may differ materially from such forward-looking
statements as a result of risks and uncertainties, including those
described in Metricom's 1998 Form 10-K and other reports filed with
the Securities and Exchange Commission.