Rush Limbaugh this week revealed the hidden story behind the two-year-old #StopRush Twitter campaign, exposing the “grassroots” effort as a Media Matters-founded automated attack kept alive by about 10 people.

Limbaugh writes:

The Stop Rush group claims to be made up of ordinary consumers unhappy with Rush Limbaugh’s comments. The group claims to be “grassroots,” just concerned consumers who won’t shop at businesses that advertise with Rush Limbaugh. In truth, however, there are no potential customers here, just a small number of hardcore political activists founded by Angelo Carusone, EVP of Media Matters for America.

It’s remarkably tiny. Only 10 Twitter users account for almost 70% of all StopRush tweets to advertisers, amplified by illicit software. In addition, almost every communication from a StopRush activist originates from outside the State of the advertiser. Thus, these activists are not and never would have been customers… their only role is to harass small businesses in an attempt to interfere with their operations, as long as they are advertising with Rush.

Rush Limbaugh Show spokesperson Brian Glicklich tweeted screenshots of the online operation.

Investigative reporter Sharyl Attkisson, who writes about astroturfing in her upcoming book “Stonewalled,” reports that the #StopRush “brigade” includes a woman who emails from her official Kent State University account.