Letter writing will only work if it's coordinated and done by a hell of a lot of people.
I think that sort of thing saved the show, "Roswell."
http://www.austinchronicle.com/gyrobase/Issue/story?oid=oid%3A84689A subsequent letter-writing campaign swelled around CBS's Cagney & Lacey in 1982. This effort ushered in the show's eight-year run and led to the formation of Viewers for Quality Television, according to Howard Wen in "Revolt of the Couch Potatoes" (Salon.com in 1998,
www.salon.com/21st/feature/1998/08/24feature.html ). Today, Web rings, authorized and unauthorized fan sites, newsgroups, and simple e-mail can rally fans in the click of a few keystrokes. Although an online campaign failed to save another CBS drama, Brooklyn South, a more recent campaign by Roswell fans convinced the WB (which then carried the series) to renew the show. The campaign was a double whammy of sorts. Instead of just flooding the network with e-mail, fans decided online to snail mail bottles of Tabasco sauce to WB execs. The ploy was clever in that it provided the networks with tangible evidence of the show's fan base; media observers say network execs take greater stock in snail mail than in e-mail, because snail mail takes more thought and effort to execute. The campaign also brought a bit of playfulness to the ordinary complaint letter. Tabasco sauce is the beverage of choice for the alien teens on the series.
