A recent court ruling in Illinois has vast implications for direct marketers. And if there's one lesson DMers must take from the decision it's this: Rightly or wrongly, simply complying with Can Spam is not enough to get e-mail delivered.

It doesn't matter if the sender's list is triple-verified-we-even-called-just-to-make-sure opt-in, if an Internet service provider decides a mailer's e-mail is spam and blocks it, the ISP has every legal right to do so.

In April, Judge James B. Zagel of the U.S. District Court in Northern Illinois determined that Comcast is not liable for mistakenly blocking even permission-based e-mail when it's part of a good-faith effort to protect its subscribers from spam, nullifying a lawsuit brought by e360's CEO Dave Linhardt against the cable broadband provider.

Comcast is America's No. 2 ISP with 13.2 million subscribers and a 13.5% share of the market, according to ISP Planet. Linhardt sued Comcast in January, accusing it of unfairly blocking messages that he said were permission based. However, Judge Zagel ruled that Can Spam compliance “does not evict the right of the provider to make its own good faith judgment to block mailings.”

He added: “Under the law, a mistaken choice to block, if made in good faith, cannot be the basis for liability under federal or state law.”

Get that? Even if ISPs mistakenly block permission-based e-mail, as long as it's part of a legitimate effort to protect their bread and butter — subscribers — from unwanted mail, they're fine from a legal standpoint.

Put more succinctly for marketers that think permission means the right to demand delivery: Internet service providers are on the power end of the e-mail sender/receiver relationship. They don't care about e-mail marketers' business models. They don't care if the addresses are single, double or triple opt-in. They care only about their subscribers and whether they consider messages to be spam.

Also, people's sentiments are with the ISPs on this issue — judges are people, remember? — and these sentiments are not likely to change. Marketers that get e-mail blocked have only one option: Figure out whatever it is they're doing that makes their messages look spammy and change it.

Laura Atkins of deliverability consultancy Word to the Wise recently published a very straightforward list of do's and don'ts for people whose e-mails are getting blocked that explains how they should deal with ISPs.

Among them: “Do not mention Can Spam. That's like saying ‘I do the bare minimum the law requires and expect you to accept my mail anyway.” And: “Do not ask them to remove the block. Ask them what you did to get blocked and how to avoid being blocked in the future.”

She also says marketers should refrain from making threats. “There is nothing you can threaten them with that they haven't heard before,” she writes. “Do not lecture them about the law. It is unlikely you understand the law better then they and their lawyers do.”

I've said it before. I'll say it again. E-mail deliverability is largely about list hygiene and message relevance, which means it is also largely in the list owner's control. Don't send messages to bad and inactive addresses, and don't send crap to the good addresses.

Pretty simple, really.