MSN had offered its 187 million active Hotmail users the ability to read and send e-mail through the e-mail clients rather than a Web interface using a protocol called Web-based Distributed Authoring and Versioning, or WebDAV.
But as of Monday, news users wanting to make use of WebDAV will have to pay for the service, said Brooke Richardson, product manager for MSNs communications services. MSN plans to transition current WebDAV users to subscription plans in the next few months as well.
"We really wanted to try and keep it available to customers for free," Richardson said. "[But] in the last few months we were seeing spammers going more and more after this particular protocol."
WebDAV-based spam abuse has risen following anti-spam measures over the past year, such as enforcing a 100-message daily cap and requiring the solving of proofs to open accounts, Richardson said. The latest move targets spammers who are writing automated scripts for WebDAV to send the daily maximum amount of e-mails from multiple Hotmail accounts.
Hotmail users now will have to sign up for one of two MSN Hotmail subscriptions to gain Outlook access—either MSN Hotmail Plus for $19.95 a year or MSN Premium for $99.95 a year, Richardson said.
Richardson said the subscriptions will allow MSN to better find and thwart spammers because the company will have a record of credit card and other identifiable information on account holders.
WebDAV is a set of HTTP extensions that allows for the reading and writing of documents through the Web. MSN Hotmail was one the few Web-based e-mail services to offer free downloading of e-mail to clients, and between 5 percent and 7 percent of users signed up for it, Richardson said.
Most other services, such as Yahoo Inc.s Mail, include it in premium offerings and use the POP3 (Post Office Protocol 3) standard.
MSN Hotmail in June jumped into the Web-based e-mail storage race with plans to give users 250MB of free storage—up from 2MB—and to increase storage for paying customers to 2GB.
The upgrades for free users have hit some snags. Richardson confirmed that MSN is slightly behind schedule in completing the upgrade.
MSN has begun converting based on seniority, but it now expects to complete the upgrade by the end of the year rather than in the fall, Richardson said.
"We are seeing customers consuming more storage than we anticipated, and were bringing more storage online," she said.