Citing concerns about spammers abusing the service, Microsoft will announce today that the company is dropping a feature from its Hotmail service that lets nonpaying customers access their Hotmail email from Microsoft Office Outlook and Outlook Express. The feature is based on a technology called Distributed Authoring and Versioning (WebDAV), an extension of the HTTP protocol on which the Web is based. 
  
"Since we implemented Human Interactive Proof (HIP) to ensure that only humans and not automated systems were opening Hotmail accounts, spammers have found other ways to go after the system," MSN Lead Product Manager Brooke Richardson told me in a prebriefing Friday. "Recently, there's been an increase in exploits of the WebDAV protocol, which is used to enable people to access Hotmail from Outlook and Outlook Express. We've offered [this access] for free for some time, although it's typically a feature that other email providers charge for. But because of the rise in abuse of this protocol, we're making a change to WebDAV to curb abuse. Over the next few months, we're transitioning WebDAV to be available only to customers of our subscription services, such as Hotmail Extra Storage and MSN Premium. We expect this change will help us to more effectively stop spam emanating from Hotmail."
  
Richardson said that only a small percentage of free Hotmail account holders use the WebDAV feature. "About 5 to 10 percent of people have it set up," she said, "but most don't use it. And among that group, most activated it once, then never used it again. About 95 percent of our users don't use the feature." Richardson was also careful to note that this change doesn't mean that Microsoft is walking away from its nonpaying users. "We continue to invest heavily in Hotmail," she said. "We've recently instituted antivirus scanning and cleaning and brought back the [free] MSN Calendar. And we're actively moving free customers to the new storage allotments we announced earlier this summer." Richardson said that the company will upgrade storage allotments for all free Hotmail accounts by the end of the year. Microsoft has already upgraded paying customers, such as those who opted for Hotmail Extra Storage, she said.
  
Microsoft won't immediately shut off nonpaying users who have enabled Outlook or Outlook Express access to Hotmail. Instead, the company will phase out those customers over several months and give them plenty of warning that the change is coming. "Free Hotmail customers who want to use WebDAV have two choices," Richardson said. "They can opt for Hotmail Plus, which offers 2GB of storage space and 20MB attachments for just $19.95 a year. Or they can subscribe to MSN Premium." Microsoft will continue to enable WebDAV for customers of both products, she said.
  
For more information about Hotmail Plus, visit the MSN Web site. For more information about MSN Premium, click here .