One of these days, a Guide to Avoiding the Errors of the Facebook Empire will be written. At least one chapter will include the back-and-forth by Facebook-owned Instagram over the last couple of days.

On Tuesday in a posting on the company's blog, Instagram's co-founder promised to fix the terms in two new documents, its Privacy Policy and Terms of Service, which were introduced on Monday and scheduled to take effect in 30 days. Users launched the online equivalent of storming the Bastille as word spread that the documents would allow Instagram -- and its parent, Facebook -- to sell photos posted by users, without users' permission or compensation. Many users angrily reported that they were deleting their Instagram accounts.

Co-founder Kevin Systrom said he was writing on the blog to "let you know we're listening and to commit to you that we will be doing more to answer your questions, fix any mistakes, and eliminate the confusion." He added that, "as we review your feedback and stories in the press, we're going to modify specific parts of the terms to make it more clear what will happen with your photos."

'Language Is Confusing'

Systrom said that the new documents were intended to "communicate that we'd like to experiment with innovative advertising that feels appropriate on Instagram," but it was "interpreted by many that we were going to sell your photos to others without any compensation." However, he said, this is "not true and it is our mistake that this language is confusing." The company is working to clarify the language, Systrom added.

He also said that Instagram users own their own content and the company "does not claim any ownership rights over your photos." Additionally, he said, nothing has changed in terms of privacy settings and the control that users have over who can see their photos.

The new documents present a variety of terms-of-use that raised the ire of users. In them, for instance, Instagram said it could share data about its users with Facebook and outside advertisers and affiliates. It also said that users agreed that "a business or other entity may pay us to display your username, likeness, photos (along with any associated metadata), and/or actions you take, in connection with paid or sponsored content or promotion, without any compensation to you."

Ads Not Labeled

This section not only claimed to be able to incorporate a users' photos without payment or consent, but, by implication, it applied to anyone -- famous or not -- whose image was in those photos. Instagram account owners need to be at least 13 years old, and the company said the terms applied to those underaged users as well.

The new documents also specified that "paid services, sponsored content, or commercial communications" will not always be labeled as such, meaning that users could not tell what was an ad or not.

In addition, the company said that by using the Web site, a user agreed to the terms. The only apparent way to opt out was to cancel one's account, which many users have done.