Back then many companies ran a free, open-source e-mail relay technology but ended up spending more than they thought they would making the stuff work.

FORBES: You Get What You Pay For

Some use "mail relay, " borrowing someone else's domain to send e-mail.

FORBES: Spam Warfare

Back in the early 80s a man by the name of Geoff Goodfellow had an idea: to relay electronic mail from Arpanet to his alphanumeric pager.

ENGADGET: Geoff Goodfellow, early inventor of wireless email, profiled

Corporate customers have installed some 40, 000 BlackBerry servers, which synchronize and relay e-mail and let data-processingdepartments remotely zap all the data from lost or stolen BlackBerrys.

FORBES: BlackBerry Jam