While Yahoo, AOL, Microsoft and Google waded into the battle this week against spammers and Internet scammers, stealth mode start-ups and others small vendors are gearing up in hopes to ignite the newest fight against malicious use of e-mail and the Internet.

Yahoo, AOL, Microsoft and Google this week became flashpoints in the contentious debate around spam, blacklisting and online ethics. Yahoo and AOL took center stage by offering bulk e-mail senders the option of paying to certify delivery of e-mail to end-users.

In the U.K., a number of legitimate retail companies accused Microsoft of unfairly blacklisting them and cutting them off from Hotmail users. And Google raised eyebrows in Germany by giving BMW the “Google death sentence” by dropping the carmaker’s search rating to zero after it spiked its Web site to manipulate search results.

The issues all shed light on the fact that the Internet continues to be a tough place to do business. And the fact that these incidents are happening as the discussion rages around telecom providers and the issue of ‘Net neutrality is only heightening concerns.

The problem is no more apparent than with e-mail, where spammers are winning a cat-and-mouse game while end-users lose confidence in the Internet’s killer application.

In an effort to restore some confidence, companies like certification start-up Goodmail Systems and a stealth start-up working behind the Web address Karmasphere.com are attempting to pull together authorization, accreditation and reputation systems that may eventually help clean-up in-boxes and push the cost of spam onto spammers.

Yahoo and AOL, who will be the first Goodmail customers, view their forthcoming service in that vein.

However, critics were quick to point out that the service would not help curb spam, while others accused AOL and Yahoo of taxing legitimate e-mail senders.

“This is not a spam reduction measure,” says Andrew Lochart, senior director of marketing fro anti-spam vendor Postini. “It is a way for a legitimate merchant to avoid getting a false/positive in an AOL spam filter.”

AOL agrees with that general assessment and says the certified mail service is but one option for e-mail delivery in addition to AOL’s free White List ranking and plain old Internet e-mail delivery.