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Twitter has apologized for an embarrassing marketing gaffe this week that showed people tweeting enthusiastically about products they had never seen before.

The snafu occurred Tuesday when the San Francisco Chronicle discovered a blog post that showed three real Twitter users tweeting things like, “I wish could make fancy lattes like in the @barristabars commercial.” The Twitter users reacted angrily to their images being co-opted for sample endorsements. The company updated the blog post on Wednesday with a new heading:

“An earlier version of this blog post included an image with mock Tweets from real users of our platform. This was not OK. Once we became aware of this mistake we took it down immediately. We deeply apologize to the three users included in the earlier images.”

The apology, along with the fact that just three users were affected, suggests the incident was an internal screwup and not, as some have suggested, a nefarious plan to force Twitter users to endorse things against their will. This has not, however, stopped user Neil Gottrieb from telling the Chronicle that he may sue for unauthorized use of his likeness.

The episode raises the familiar question of how far social media companies can go in harvesting user images and content for advertising. Twitter and other companies regularly offer assurances that users own their pictures and images. But, while this is technically true from a copyright perspective, the companies also impose licenses that let them do nearly anything they like with the images.

In the case of Twitter, a key part of the terms of service reads like this:

You agree that this license includes the right for Twitter […] to make Content submitted to or through the Services available to other companies, organizations or individuals who partner with Twitter for the syndication, broadcast, distribution or publication of such Content on other media and services […] with no compensation paid to you with respect to the Content that you submit

Such provisions can trump state laws that protect individuals’ right to control their commercial images — though it’s unclear if it would protect Twitter from a fabricated endorsement.

Twitter’s mistake recalls similar stumbles by Facebook(s fb) and Instagram as they moved towards commercializing their users base. In the case of Facebook, the company had to settle a suit over “sponsored stories” for using people’s likeness to endorse products without their consent; the social network has since updated its terms of service to allow this.