Microsoft is running a high-profile ad campaign positioning its Windows Live Hotmail service as a tool for the "New Busy." The meaning is open to interpretation, but we're pretty sure that even the New Busy are allowed to go on vacation. But for now, at least, they won't be able to use an automatic reply to let people know when they do.

The company has turned off the vacation reply feature in Hotmail, explaining in a recent blog post that it's a temporary measure meant to prevent the automatic reply mechanism from being misused by spammers.

"In our fight against spam, we sometimes have to make hard choices, and we had to make one this week. We discovered that spammers were using Hotmail’s automatic vacation reply feature to send spam from their Hotmail accounts," wrote the Hotmail team in the April 8 post. "We decided to temporarily shut off the feature in order to shut down the spam. Of course, we know some of you like and use automatic vacation replies to let people know when you can’t respond to e-mail for a while, and we’ll turn this feature back on as soon as we’ve worked out the best way to prevent it from being misused by spammers."

It's part of a broader effort by the company to fight the abuse of Hotmail by spammers, and obviously the problem was severe enough in this case to warrant turning off a feature, in the view of the company.

But the ironic thing is that Microsoft -- which routinely sends out promotional messages to Windows Live users -- doesn't appear to have sent out an email alerting them to this change. I searched my Hotmail archive, without success, and the Hotmail user who alerted us to the issue discovered the explanatory blog post only after trying, in vain, to find the feature.

"As a sole proprietor who uses Hotmail for clients, this could have a direct impact on my business," the user wrote in an email.

Asked for an update last week, a Microsoft representative said there wasn't yet any further information to share beyond the details provided in the blog post. I'm making a note to check back in on this one periodically in the coming weeks, and we'll provide more information as it's available.