Ire over cap-and-trade is helping conservative groups grow their Rolodex of supporter e-mail addresses this summer as their online advocacy efforts enjoy unprecedented participation levels.

One is Freedom Works, which generated over 40,000 e-mails to Congress during a July 4 call to action to defeat the climate change bill, according to the conservative group's press secretary Adam Brandon. It was a "tremendous spike in activity," he said.

The Campaign for Working Families and the John Birch Society, both conservative groups, also staged e-mail campaigns to defeat the climate change bill, but would not release participation numbers, saying only that they have fielded increased online support thanks to dissatisfaction with the legislation.

The burst of emails during the July 4 recess led some members of Congress to perceive salient opposition to the bill, according to Doug Thornell, an aide to Rep. Chris Van Hollen, D-Md., who voted in favor of the bill. But those on the left question whether there really is growing opposition. Thornell said some theorize that the e-mails really reflect a small contingent of opposition "brought together by Fox News, the right wing blogs, and conservative talk radio."

But that might not matter. The most significant impact of the e-mail campaigns may not be changing minds on Capitol Hill for these conservative groups but, rather the opportunity to gather e-mail addresses from voters in the heartland. Freedom Works has collected over 17,000 new supporter e-mail addresses since February from people interested in energy and cap-and-trade, according to Brandon.

Collecting a large database of supporter e-mail addresses is an essential step in online organizing. "Mass emails are about the least effective way to advocate. But when you use it to get someone to make a phone call, that, all of a sudden, is a very big deal," said Colin Delany, the founder of e.politics, a site about online organizing.

For Freedom Works, each new e-mail address represents an opportunity to rear a new small government advocate. "The real value added is when you keep moving these people up the food chain on any issue," Brandon said.

Conservative groups have generally lagged behind progressive groups in web organizing success, but Brandon believes online efforts will surge thanks to the newfound wealth of galvanizing issues the Obama administration and the Democrat Congress have proposed, like climate change legislation.

"It's clear now when one [policy] is for expanding the role of government, and one is not," Brandon said. "It's so easy" to get people motivated.

Members of Natural Resources Defense Council condemned the conservative group's strategy of using climate change to build membership. Pete Altman, an NRDC climate change director, characterized the Freedom Works strategy as latching onto climate change to further the "broader agenda of opposing progress." He added that: "Clean energy and climate are basically being used to try to propel [these conservative groups] forward."

Thornell echoed the sentiment. "The right wing is looking for any opportunity to mobilize their supporters, and they're trying to find a good fundraising boogeyman," he said.