via @liberationtech and Wikipedia
Netroots is a term coined in 2002 by Jerome Armstrong to describe political activism organized through blogs and other online media, including wikis and social network services. The word is a portmanteau of Internet and grassroots, reflecting the technological innovations that set netroots techniques apart from other forms of political participation. In the United States, the term is used mainly in left-leaning circles.
The term necessarily overlaps with the related ideas of e-democracy, open politics and participatory democracy, all of which are somewhat more specific, better defined, and more widely accepted. Netroots outreach is a campaign-oriented activity that uses the web for complementing more traditional campaign activities, such as collaborating with grassroots activism that involves get-out-the-vote and organizing through interconnecting local and regional efforts, such as Meetup, and the netroots-grassroots coalition that propelled the election of Howard Dean to the DNC Chair in January, 2005.
At times the term netroots is used interchangeably with the term blogosphere, though the blogosphere is considered a subset of netroots in that blogosphere describes just the online community of blogs, where netroots includes that plus a number of larger liberal on-line outposts such as MoveOn, Media Matters for America and Think Progress.
Advocates claim that the essential quality of the netroots is its flatness and inter-linked web connectiveness — that it constitutes communication points that reach out to influence traditional media, but is not directed outward from any one point. Through events like a blogswarm, the netroots displays non-hierarchical and decentralized features.