A 1996 podcasting patent is in the crosshairs of two digital rights groups, which are hoping the public will help them get the patent invalidated.

The Electronic Frontier Foundation, partnering with the Cyberlaw Clinic at Harvard University's Berkman Center for Internet and Society, is asking the public to identify examples of ideas similar to podcasting that were published before Oct. 2, 1996.

A Texas company, Personal Audio, holds a 2012 patent for a system for disseminating media content representing episodes in a serialized sequence and a related 1996 patent for an audio program player including a dynamic program selection controller.

In April, Personal Audio filed lawsuits asserting its podcasting patent against NBC and CBS, and in January, it filed lawsuits against ACE Broadcasting Network, HowStuffWorks.com and TogiEntertainment.

Personal Audio didn't immediately answer an email seeking comment on the EFF's planned challenge to its patents.

The EFF and the Cyberlaw Clinic are targeting the patent using a new legal tool for challenging existing patents at the U.S. Patent and Trademark Office, called the inter partes review. The new challenge was part of the America Invents Act, passed by Congress in 2011.

The EFF is asking the podcasting community to submit evidence of podcasting-type technologies that existed before late 1996, and the group is also asking for funding to fight the patent. The EFF's goal is to end Personal Audio's lawsuit threats, said Daniel Nazer, an EFF staff attorney.

"A podcaster working out of a garage is unlikely to have the financial resources to fight a lawsuit," he said in an email. "Patent trolls like Personal Audio know this and use the threat of ruinous litigation costs as a weapon."

Crowdsourcing is a good way to get ideas on so-called prior art, "especially those that were involved in pioneering early Internet media," he added."The history of the early web is in a lot of different hands and minds -- a public call for prior art can find material we would otherwise miss."

Nazer discounted a suggestion that the patent could be legitimate.

"Episodic internet radio was pioneered in the very early 1990s," he said. "Given the breadth of the patent's claims there may be many other kinds of media to consider as prior art."