Allaire left Macromedia in February 2003 to join venture capital firm General Catalyst as a technologist and executive-in-residence.

[5] From 1990 until his graduation, Allaire became obsessed with the Internet and how it could be applied to transform systems of communications and media, as well as its impact on fundamental human rights, such as free speech.

He was an early follower of the Electronic Frontier Foundation, and later recruited EFF founder Mitch Kapor to the board of directors of Allaire Corporation.

In 1992 and 1993, with a college friend, Allaire developed an application called "World News Report" that aggregated news feeds and mailing list content from independent media sources on the Internet, and provided a full-text indexed browsable and searchable interface to access independent journalism on the Internet, using Apple Hypercard.

[4] At Macalester, Allaire became more politically active, finding a particular interest in U.S. foreign policy and global human rights issues, including the impact of the collapse of the Soviet Union, the rise of authoritarian capitalist regimes in the east, and the Balkan Wars.

[5] In the fall of 1993, he launched an Internet-consulting firm, Global Internet Horizons, aimed at helping media publishers and marketers understand and build a presence on the nascent World Wide Web.

[7] ColdFusion was widely used, and companies including Myspace, Target, and Toys R Us (along with millions of other websites) relied on the technology to develop their online properties.

In addition to its flagship product ColdFusion, Allaire launched HomeSite, which became the world's most popular Windows HTML editor, and JRun, one of the first and most widely adopted Java app servers.

He started an internal product project at Macromedia code-named "Vista" that enabled easy browser-based capture, upload and publishing of video into any website, blog or instant message.

[17] But Allaire and his planned SPAC partner, the CEO of Concord Acquisition Corp Bob Diamond, called off the merger for reasons concerning recent market conditions and current events and agreed to the termination of the July 2021 intended SPACoff.