• by Wendy Davis , Staff Writer @wendyndavis, July 28, 2016

The United States Olympics Committee appears to be gearing up for a showdown over ads on Twitter, Facebook and other Web platforms.

The organization recently told advertisers that sponsor athletes, but don't also pay multi-millions to sponsor the USOC or International Olympic Committee, to refrain from using hashtags connected to the Olympics.

"Commercial entities may not post about the Trials or Games on their corporate social media accounts," USOC chief marketing officer Lisa Baird wrote, according to ESPN. "This restriction includes the use of USOC's trademarks in hashtags such as #Rio2016 or #TeamUSA."

Whether the Olympic Committee can enforce its demands is another matter -- one that may turn out to be surprisingly complicated.

To a large extent, questions about trademark infringement on Twitter may hinge on unresolved questions about when tweets are actually ads -- according to Santa Clara University law professor Eric Goldman.

Some tweets are obvious ads, but others exist in a gray area. Consider, two years ago drugstore chain Duane Reade landed in court after boasting on Twitter that actress Katherine Heigl shopped at the store. The company posted a photo of Heigl walking on a street while carrying large shopping bags with the store's logo on them, along with the now-deleted tweet: “Love a quick #DuaneReade run? Even @KatieHeigl can't resist shopping #NYC's favorite drugstore.”

That tweet prompted the “Knocked Up” star to sue the drugstore for turning her into an unpaid endorser. Experts weighed in on both sides of the dispute, but it was settled before any judges ruled on the matter.

But even if a brand posts something that's clearly an ad, and uses a hashtag like #TeamUSA, the advertiser hasn't automatically infringed trademark, according to Goldman.

Instead, judges look at questions such as whether the post duped consumers into believing the brand was affiliated with the trademark owners, Goldman says. Even if the answer is yes, brands can still argue that they have a free speech right to use hashtags that describe an event like the Olympics games.

There's no good way to predict whether advertisers or the USOC would prevail on those questions, if disputes end up in litigation. But the USOC may not need to go that far. If the organization believes its trademarks are being violated, it can always complain directly to Twitter -- which may then make its own decisions about removing the posts. And Twitter, unlike the U.S. government, is always free to censor tweets regardless of how legitimate they are.