The bill has come under criticism for being weak, and for legalizing certain forms of spam while including provisions that make it easier for illegal spammers to get away with it. CAN-SPAM will likely live or die by how effectively it is enforced.

The bill lets certain federal agencies and states’ attorneys general bring criminal charges against suspected spammers. It also allows ISPs to bring civil complaints against individuals they suspect of breaking the new law.

Several attorneys general, including those in tech-heavy Virginia and California, last month spoke out against CAN-SPAM, calling it weak and pointing out more than half a dozen loopholes, some of which have since been tightened in the final draft of the bill.

However, many consumer ISPs, such as America Online Inc, EarthLink Inc, Microsoft Corp and Yahoo! Inc, backed the bill. When CAN-SPAM is passed, these firms and others will be watched to see if they can back up their support with actions.

I think we are planning on using it. We have a critical interest in fighting spam, said Dave Baker, director of law and public policy at Atlanta-base EarthLink. You can expect we and all other ISPs will use this new law as intended.

It’s fair to expect we will take this law and try to use it to improve the online experience for our customers, said Microsoft spokesperson Sean Sundwall. It’s safe to say when the time comes for us to take action, it will be publicized.

Some people, prominently California state senator Debra Bowen, whose state law will be pre-empted by CAN-SPAM, say AOL is part of the spam problem, and that lobbying for CAN-SPAM was mostly an effort to protect itself.

According to Bowen, CAN-SPAM, gives Microsoft, America Online, and millions of other advertisers and marketers everything they asked Santa for. The bill doesn’t can spam, it gives it the congressional seal of approval.

Microsoft’s Sundwall said: The key word here is customers, any company would be reticent to give up its right to communicate with its customers.

CAN-SPAM permits most spam as long as it has a working opt-out link. Critics say that this could actually make the spam problem worse, given that many spammers already use phoney opt-out links as a means to verify their victims’ identities.

Spammers, including those who fall geographically outside CAN-SPAM’s jurisdiction, will likely start making their spam look legal, with opt-outs. When victims start to realize these opt-outs do not work, they will be less likely to opt out of the legal spam.

According to EarthLink’s Baker, once spammers start to go to jail, the effects of CAN-SPAM will be felt. This bill is unique in that it has criminal provisions, he said. This is where we think the real teeth of the bill are.

EarthLink has found that civil actions can lead to subsequent criminal prosecutions, such as in the case of Howard Carmack from Buffalo, New York, who earlier this year lost a civil case against EarthLink and was subsequently arrested for suspected identity theft.

Time will tell how seriously ISPs take CAN-SPAM and precedent does not give a clear indication. Anti-spam state law in Microsoft’s home state of Washington sat idle on the statute books for five years before Microsoft brought suit under it, for example.

However, Microsoft, AOL, Yahoo and EarthLink have all sued suspected spammers, using legislation that does not directly refer to spam but which covers some practices spammers employ, such as identity theft, trespass and hacking.

This article is based on material originally produced by ComputerWire.