Open-Xchange's tool for helping people reconstruct their Facebook contact list on Google+ has fallen victim to Facebook's revocation of its privileges.

Open-Xchange, a maker of open-source e-mail and collaboration software, last week launched a tool that used the company's Social OX technology to help people assemble a list of their friends. It used connections to a combination of services such as LinkedIn and e-mail accounts to create a single "magic address book."

The tool didn't actually copy e-mail addresses from Facebook--only first and last names. It then matched those names to other e-mail records in the user's accounts. But Facebook disabled the API (application programming interface) key that the software used to read the names, Open-Xchange Chief Executive Rafael Laguna said.

Facebook gave two reasons for the move and underscored the seriousness of its decision with a warning about the repercussions:

1. You cannot use a user's friend list outside of your application, even if a user consents to such use, but you can use connections between users who have both connected to your application. (FPP II.11) 2. A user's friends' data can only be used in the context of the user's experience on your application. (FPP II.4) Please note that we will not re-enable violating applications and any policy issues in your existing and future apps will result in further enforcement actions.

Facebook told CNET its actions are an aspect of protecting Facebook users. "The people who use Facebook expect us to protect the information they share with us, and prevent phishing, malware and scraping whenever possible. We are always reviewing and revising our user protections, and when we come across Platform integrations which violate our terms, we respond quickly," the company said in a statement.

Laguna objected to Facebook's decision. In a letter to the company, he said:

We are not aware of violating anything. We are using your API to extract the last name and first name fields. We are not parsing or scraping the e-mail address. That same data is available at your site under "Account->Account Settings->Download Your Information" in the resulting friends.html file.

This isn't the first time Facebook has made such a move. Facebook also blocked use of a Chrome extension by programmer Mohamed Mansour that would export not only names but also e-mail addresses, phone numbers, birthdays, and more. Mansour's tool didn't use Facebook's API for programmatic access, but instead extracted the data from the pages themselves.

The matter of who owns address-book data in Facebook was a hot one last year, when Google and Facebook got into a spat about contact-data sharing. But now that Google finally has what appears to be a viable competitor to Facebok, the issue is a really hot one.

Google probably only has something like a hundredth of Facebook's population. But with one Google+ user base estimate exceeding 4 million people, that's still pretty significant in absolute terms.

Some of the issue about the Facebook data is semantic. If you call it your address book stored within Facebook, it seems more like you should be able to get access to that information. After all, it's information your friends have shared with you. But if you think of it as your friends' own profile data, the ownership claim doesn't look as strong, regardless of the matter of whether they agreed to share.

Fundamentally, though, there's nothing stopping people from copying each e-mail address manually from Facebook. The problem crops up when such extraction is automated.

Which is why the Yahoo position is so peculiar. Anyone with a Yahoo Mail account can easily extract not only the names but the e-mail addresses of their Facebook friends. If you want to try this method, first open a fresh e-mail account at Yahoo. As soon as it's created, you'll get an option to import contacts from elsewhere, including Facebook. Choose that option, authorize the tool, and it'll import the contacts.

To make them useful in Google+, you'll then have to transfer them to Google by exporting a CSV (comma-separated values) spreadsheet. Gmail lets you import a CSV file by clicking Contacts, then the More actions button, then the Import menu item. Of course you can use the CSV file elsewhere, too.

Laguna asked how it's possible for Yahoo to extract the data but not others.

"Is there a way to get sanctioned or even paid access?" Laguna asked, then raised the matter of the two objections Facebook raised about Open-Xchange. "You must have some kind of arrangement with Yahoo, which even has an import capability of not only the names but also the Facebook e-mail addresses? How can Yahoo do it without violating points 1 and 2 above?"

Facebook wouldn't comment on the Yahoo export tool.

Updated 2:28 p.m. PT with Facebook declining to comment.