Montana Republican Sen. Conrad Burns and Oregon Democratic Sen. Ron Wyden introduce bill that would require Internet marketers to provide legitimate return addresses with their crap:

"This bill will help to keep legitimate Internet traffic and e-commerce flowing by going after those unscrupulous individuals who use e-mail in annoying and misleading ways," Wyden said in a statement.

Offers for "herbal Viagra" and urgent requests for assistance from "Nigerian colonels" have become an annoying constant of online life.

But spam has grown from nuisance to threat status over the past year as the volume of unwanted messages exploded.

The bill would not allow consumers to sue spammers directly, but require state attorneys general to sue on their behalf. The Federal Trade Commission could also fine violators, and Internet providers could block spammers from their networks.

Internet portal Yahoo! said it supported the bill, while the DMA and Internet provider America Online said they would work with the Senate to craft an effective bill.

The average "wired" American received more than 2,200 spam messages last year, according to Jupiter Research, while the British government said last month that spam now accounts for 40 percent of global e-mail traffic. [Reuters]