Yahoo Mail Classic is now dead. Yahoo Mail users, as of Monday, no longer have the option of using the old version, and must instead use the new version, which Yahoo reminds them, serves ads based on the content of their emails, much like Google’s Gmail has always done. As one might imagine, a lot of users are less than thrilled about this.

What do you think of the new Yahoo Mail? Let us know in the comments.

“Beginning the week of June 3, 2013, older versions of Yahoo! Mail (including Yahoo! Mail Classic) will no longer be available,” wrote Yahoo in its help center fairwell (via TechCrunch). “After that, you can access your Yahoo! Mail only if you upgrade to the new version. You should have received an email from Yahoo! letting you know that your account required an upgrade.”

Yahoo noted that when you upgrade, you are accepting its Communications Terms of Service and Privacy Policy, which includes the acceptance of “automated content scanning and analyzing of your communications content, which Yahoo! uses to deliver product features, relevant advertising, and abuse protection.”

“If you prefer to opt out of interest-based and contextual-based advertising resulting from your scanned and analyzed communications content, you can change your settings at any time using our Ad Interest Manager,” Yahoo said.

So, it’s even letting you opt out of ads, but that doesn’t mean they won’t scan your mail. You still have to accept Yahoo’s terms.

Those who don’t want to use the new Yahoo Mail were directed to download their mail using IMAP or close their account.

Yahoo’s mention of scanning email to serve ads comes as search partner Microsoft has been campaigning against Google for doing just that, despite the fact that Google has always done this, and has always been quite clear about it.

To many people this really isn’t a big deal. Gmail hasn’t had any shortage of users, and it’s not as though humans are reading users’ email to try and determine which ads to show. It’s all automated. Those who are concerned about this practice, however, could play right into Microsoft’s hands.

Suddenly the timing of Microsoft’s campaign seems a lot better from a marketing standpoint. It seemed odd that Microsoft would attack Google suddenly for something it had been doing for nearly a decade and made not efforts to hide. But now we have the previously announced Yahoo Mail redesign, which engages in similar practices as Google, being forced on users. Could Microsoft users have made enough Yahoo users uneasy about this practice in general to get some of them to switch over to its own Outlook.com (the focal point of that particular “Scroogled” campaign)?

As Declan McCullagh at CNET points out, Yahoo actually adopted the policy that lets it scan emails and serve ads back in 2011. He writes:

It’s not clear why Yahoo felt the need to remind existing users of language in its 2011 terms of service. One possibility, though, is an effort to head off privacy lawsuits brought by class action lawyers hoping for a million-dollar jackpot. (If there’s ever any litigation, defense counsel would surely prefer to rely on informed consent rather than implied consent.)

It’s not merely a theoretical possibility: Google was sued in 2011 by a Massachusetts AOL user who sent e-mail to a Gmail account and then claimed her privacy was invaded. Near-identical lawsuits were filed in Marin County, Calif., (PDF) in June 2012, British Columbia (PDF) in October 2012, and Florida (PDF) in November 2012. On April 29, two college students filed yet another suit (PDF) seeking class action status in San Jose, Calif.

The shuttering of Yahoo Mail Classic also comes on the heels of a separate Yahoo Mail privacy-related story. Last week, a BT made some headlines when it said it would no longer make Yahoo Mail the default email service for its six million customers because of concerns that accounts are vulnerable to getting hacked.

Gerry Smith at The Huffington Post writes, “The shift of BT’s 6 million customers to another email service represents just a small fraction of Yahoo’s overall email customer base of about 280 million people worldwide. But the loss of clients could be a troubling sign for a company that relies heavily on maintaining its email users to generate advertising revenue. Yahoo is now the third-largest email provider after Google’s Gmail and Microsoft’s Outlook.com.”

Meanwhile, the top dog, Gmail, continues to make efforts to stay ahead of the competitive curve. Last week, Google announced the launch of the new inbox for Gmail, which introduces a new tabbed organization interface.

Privacy concerns aren’t the only thing bothering users, however. Business Insider conducted a survey, finding that 57% of users are unhappy with the new Yahoo Mail. Nicholas Carlson lists a few of the specific complaints users shared:

“The mail message frame is not fixed. If you read a new message, and scroll down to the bottom and decide you don’t want to keep it, you can no longer access the delete button. Yes, obviously you can just close the email and then choose it again and delete, but that is a total waste of time and key strokes.”

“Right after the switch I was hacked and my contacts all 500 plus were gone without a trace.”

We’ve seen further complaints in the comments of our own coverage.

Users have had since December to get accustomed to the new Yahoo Mail. More on the redesign here.

Yahoo has been engaging in a lot of redesigns across its various properties. This week, Yahoo also rolled out a new look for its search results pages to go with its recently redesigned homepage. A big Flickr redesign was also recently launched.

Is Yahoo moving in the right direction with Mail? How about as a company in general? Share your thoughts in the comments.