Dot-com bubble
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Dot-com (also dotcom) companies proliferated in the late 1990s Internet bubble. The name derives from many of their names having the '.com' DNS suffix built into their company name.
A canonical 'dot-com' company relied on network effects or simply hype instead of having a business model that made money on a per-sale basis. Many of the dot-coms have now ceased trading, after having burnt through their venture capital, often without ever making a gross profit.