AOL has promised to grant email messages from qualified not-for-profit organisations safe passage through its spam filters.

The internet provider had come under attack after it said in early February that it would allow commercial bulk email senders to pay for preferential anti-spam treatment through its Goodmail's Certified Email system. While organisations that paid a fee of $3 to $4 per 1,000 emails would be provided guaranteed delivery, messages from regular senders would be routed through the firm's anti-spam filters, potentially labelling them as spam.

A group of over 50 not-for-profit organisations teamed up to protest against the plans and claimed that it created a two-tier internet where commercial organisations would receive preferential treatment over those that can't afford to pay for it.

As of press time, nearly 27,000 individuals had signed an online petition on the group's DearAOL.com website.

AOL aims to take away those doubts by offering not-for-profits free access to the system.

"We want to make sure that not-for-profits who depend on timely communication with their members get all of the privileges of this powerful medium," said Charles Stiles, AOL Postmaster in a statement.

"Our announcement today guarantees that every certified not-for-profit will get the same benefits as private-sector companies that have decided to utilize Goodmail's Certified Email system."

Danny O'Brien, activism coordinator with the Electronic Frontier Foundation and one of the backers of the DealAOL.com website, said that AOL's decision is a step in the right direction, but fails to take away all concerns.

The adapted changes still exclude official not-for-profits organisations, and keep providing AOL an incentive to tighten its the spam filtering criteria to drive sales of its guaranteed email delivery service.

"Our main worry [is, that it] doesn't remove the key problem, which is the perverse incentives of the Goodmail scheme," O'Brien said. He added that he'd like to continue the conversation with AOL.