The first online multiplayer card game
One of the largest technology trade shows
A tech recycling firm that became Newegg
An online index of web domains for sale
 
Correct Answer: One of the largest technology trade shows

A brief explanation why…

Started by The Interface Group in 1979, Comdex (Computer Dealers Exposition aka 'Geek Week') was one of the world's biggest computer trade shows (often only behind CeBIT) and said to be among the largest trade events in any industry. Following its initial 1979 show at the MGM Grand, Comdex ran 185 expos from Las Vegas to Amsterdam over the coming decades.

The event was originally exclusive to industry insiders and demonstrated all manner of computers components, peripherals, and software. However, Comdex opened its doors to the general public in the late 80s, which ultimately ballooned attendance rates and diluted the event's focus, causing companies including IBM, Apple, and Compaq to stop participating toward the dot-com bubble.

Rights to the expo were sold multiple times after 1995 and following a peak turnout of 200,000 show-goers in 2000, only 40,000 people appeared in 2003 and by 2004 Comdex cancelled its Vegas expo, essentially conceding to CES (Consumer Electronics Show).