As major marijuana legalization groups ready their political arsenal for the upcoming election season, they’re in the usual social-media hangouts, Twitter and Facebook.

But next year, they’ve got a secret weapon: Reddit. The social news site boasts 20 million unique visitors a month, but has seen little penetration from political groups—in part because of its geeky, insular reputation and its skeptical, questioning user base.

Pro-cannabis organizations are discovering Reddit’s largest marijuana community has become a powerful political and cultural force, with a reach far beyond Reddit’s own fast-growing user base.

“I see them as a vital branch in the coming year,” John Toker of pro-cannabis group Sensible Washington told the Daily Dot. “Trees is absolutely going to prove to be one of the best ways to grow our operation.”

The obliquely named r/trees boasts a membership as big as a medium-sized city. With over 100,000 members, it’s the 25th largest community on reddit, and sees about 500,000 visits and 700 new members a day.

And pro-marijuana sentiment is far from limited to r/trees. Pot culture has gone mainstream on Reddit, one of the top 100 most trafficked websites in the United States. The most popular post of all time on r/AskReddit, another large community, is this question: “Would you support marijuana legalization if it were taxed and distributed in a way similar to alcohol?”

Last year, the r/trees community rallied around Proposition 203, a medical marijuana legalization bill in Arizona. That measure ultimately passed.

The community also frequently floods Internet marijuana petitions. Just this week, for instance, organizers of NORML—one of the oldest and most influential pro-pot organizations in the United States—contacted an r/trees moderator to ask for help getting signatures on a petition on the White House website to legalize marijuana. That petition has already gathered over 16,000 signatures, the most on the White House site.

And while it’s difficult to know how attention r/trees translates to actual votes, it’s clear pro-pot organizations take that attention seriously. The community has already worked directly with organizations in Ohio, Arizona, and California—as well as Toker’s Sensible Washington.

That group plans on launching a ballot initiative next year to legalize marijunana in the state of Washington. Toker said he believes the r/trees will be a “significant player” both in its own work and “in many other states.”

Members of r/trees—who call themselves “ents” after the calm, deliberating race of tree-people from J.R.R. Tolkien’s the Lord of the Rings—told the Daily Dot the community’s strength is built on its welcoming culture — and the pseudonymity of its members.

“Most ents cannot be truly open with themselves in their lives because enjoying marijuana automatically makes them a criminal or a burn-out loser, the obvious marijuana stigmas,” wrote redditor Wanna-Bee. “I think a lot of us can really only be true to ourselves on here.”

Erik Altieri, NORML’s communications coordinator, told the Daily Dot he thinks the anonymity of Web forums like r/trees gives a major boost to the movement. That’s because members still often face significant social stigma and potential legal repercussions for their culture in real life.

“I think it’s incredibly important,” Altieri said of the value of online pseudonomity’s at places like r/trees. “It’s probably the main impetus to how the marijuana movement picked up steam in the past year or so.”

“It allows marijuana smokers to come out of their smoking closets and realize they’re not alone,” he added.

Shaun Apple, the section’s creator, told the Daily Dot he sees that online success as a first step toward greater acceptance of marijuana culture off-line.

“r/trees needs to stand for a greater purpose, not just where people type things on the Internet,” Apple told the Daily Dot via Skype.

To that effect, organizers are launching their own non-profit. It’s called the International Cannabis Culture Education Forum. Apple hopes it will “introduce more people to the unique form of cannabis culture” of r/trees and to preserve some of the community’s best content.

“My greatest motivation is to have an effect on life outside of Reddit,” Apple told the Daily Dot.

Image via ElPablo