When sending postcards, targeting Nielsen families and recruiting new viewers doesn’t seem likely to save an endangered TV show, sometimes you must take your struggle to Twitter.

A small but mighty online force has swelled in hopes of getting nerdy action-comedy Chuck renewed for a fifth season. The latest in a series of online efforts to get NBC to commit to another chapter of the show, the We Give a Chuck campaign has been flooding Twitter with appeals to the show’s advertisers.

“The Nielsens are basically just a tool to tell a network and advertisers that people are watching the commercials aired during a show,” said Kris Schneider, one of the co-founders of We Give a Chuck, in an e-mail to Wired.com. “We decided that as fans we could tell them the exact same thing using Twitter. And unlike the Nielsens, which only seem to measure if a TV is on, we could show that not only were we watching, we were paying attention.”

The gambit is fairly simple: During airings of the show, fans send tweets to advertisers, like: “Just rewatched the last episode of #Chuck while drinking my daily @drpepper! Thanks for the Chuck support @pepsi!” The posts are then appended with the hashtag #NotANielsenFamily.

If Chuck does get renewed for a fifth season — and perhaps even if it doesn’t — the novel effort could provide a valuable lesson about social networking’s influence on old-school media. Efforts like NBC’s Fan It and entertainment check-in service GetGlue use the internet to court viewers, but We Give a Chuck’s strategy harnesses the growing reach of Twitter, which has an estimated 200 million users, and connects fans to advertisers in a very public way.

Chuck only drew 4.2 million viewers this week, but the show’s supporters hope companies will start to use Twitter as another metric for how much their ads are getting seen during the show. The organizers plan to continue their campaign each Monday when the show airs, so the concept could gain even more traction.

A previous campaign to renew the show focused on trying to find Nielsen families and getting them to tune in each week, but the advertiser-centric approach might actually be effective, at least on Twitter. The @Honda account responded Tuesday following the show’s Monday night airing with this tweet: “Thanks to the @NBC #Chuck fans for all the tweets! … #NotANielsenFamily.” The Diet Pepsi account sent out a similar tweet: “Wow! #chuck fans are awesome!”

But will the Twitter campaign guarantee a fifth season of Chuck? Hard to tell. There’s a chance a decision won’t be made until the upfronts season starts next month.

The show has been renewed during the upfronts before following a fan uprising. Chuck also took 45 percent of the votes in USA Today’s Save Our Shows poll.

NBC reps did not respond to Wired.com’s request for comment by press time.