EarthLink Inc. this week said it filed suit against two spam e-mail rings with operations in the U.S. and Canada. The ISP is suing to recover an estimated $5 million in lost employee productivity and Internet bandwidth that it claims was spent managing more than 250 million e-mail messages sent from e-mail addresses on its network, according to Pete Wellborn, outside legal counsel for EarthLink. The suit targets two separate spam operations. The first, based in Birmingham, Ala., is believed to be behinda variety of spam campaigns, including pitches for "herbal Viagra," pornography and online dating services.