Microsoft has started pushing its Sender ID anti-spam technology by running it on Hotmail.

The technology, developed by the software giant, has had a rough ride with companies questioning the terms and conditions attached to it. Many have pondered out loud whether the company is attempting to control the market by making the technology ubiquitous and then demanding licence fees.

Its decision to include it in Hotmail so that users are given an on-screen alert every time the sender of an e-mail does not use the Sender ID framework will certainly add weight to people fears, but at the same time a large number of Internet users will be glad that something is being done to tackle an ever-increasing problem.

By forcing the issue, Microsoft will at least get the issue - long delayed over standard arguments - moving. However the suggesiton by director of Microsoft's Technology Care and Safety Group, Craig Spiezle, that e-mail sent by companies that don't use Sender ID will be put in a junk mail folder or even deleted, will inevitably lead of accusations of abuse.

Spiezle laid out the changes in an interview posted on Microsoft's website yesterday. Microsoft is pushing Sender ID as a system for identifying and thwarting unwanted e-mail. The technology works by verifying that e-mails originate from the domain from which they claim to have been sent. It checks the sending server's address against a registered list of servers that the domain owner has authorised to send e-mail.

By adding it to Hotmail, Microsoft is also pushing ISPs and other businesses to publish their sender policy framework (SPF) records so that their mail does not get quashed. Businesses should publish their SPF records to "protect their domain and ultimately enhance their brand name," said Spiezle.

Microsoft is not the only major technology player promoting an anti-spam technology. Yahoo has an authentication technology called DomainKeys, and IBM has rolled out a new anti-spam technology called FairUCE, or Fair use of Unsolicited Commercial Email.

Yahoo licenses out DomainKeys, and recently said it is working with Cisco to combine their anti-spam technologies and create a new authentication system. IBM is promoting its technology with developers, saying it wants to help them build more effective antispam filters.

Additional reporting by Scarlet Pruitt, IDG News Service