In a move that could alienate it from a lion's share of free e-mail account holders, Canadian Web host GaltGroup Internet Services has turned its back on Windows Live Hotmail - as well as all the products, services and partners of Hotmail's parent company, Microsoft.

The boycott was said to have been sparked by e-mail delivery problems between GaltGroup and some of its customers who were also Hotmail users. Despite having sent legitimate, authenticated messages, GaltGroup found that Hotmail's spam filters had been directing its e-mails past users' inboxes, spam and trash folders, to be destroyed without any notice to either the sender or intended recipient.

"It is analogous to the letter-carrier just deciding to throw away your letters, and not even telling you or the person who sent it," said Laura Brownlee, GaltGroup's chief marketing officer.

"I don't believe they [Hotmail] specifically target us, but rather we fall into some category of 'things their filters dislike'," she said. "As we are unable to reliably deliver email to Hotmail and reliable email delivery is vital for billing, we simply cannot afford to take the risk to customer satisfaction that Hotmail presents."

GaltGroup no longer accepts registrants using Hotmail or MSN email address. Instead, it directs potential customers to sign up for Google's free e-mail service, Gmail.

According to Ashley Friedlein, chief executive officer and co-founder of U.K. e-commerce research group E-consultancy, deliverability problems extend beyond Hotmail to other large Web mail providers also.

Friedlein explained that some country domains, like Russia, are typically treated more harshly by spam filters, because of the volumes of spam known to originate from servers in those countries. Other servers are tagged as likely spammers by spam filters because of the number of e-mails they send within a certain time period.

"Deliverability is a real headache. It's not just Hotmail, but the other large webmail companies too - Yahoo!, AOL, Google, etc," he said. "If you send above a certain threshold you immediately get them all junked as 'spam'."

Meanwhile, a Hotmail spokesperson claimed there to be no evidence that its spam filters unfairly targets specific domains.

"We seldom get Australian customers raise issues due to the spam filters in Hotmail," said Kate Beddoe, head of Windows Live Services at ninemsn. "Our customers have told us that ensuring their email is spam-free is of top importance to them. Given this, we have worked to deliver increased security and safety measures for Hotmail."

"While we are aware of some instances where some legitimate emails in Australia have been blocked by the spam filtering technology in Hotmail, we have not received any complaints from ISPs," she said.

Beddoe said that Hotmail users are able to access spam-filtered e-mail by selecting the message in their junk e-mail folder and adding the sender to a "safe" list. This would cause emails from the "safe" email domain to no longer be classified as spam.