• by Wendy Davis , Staff Writer @wendyndavis, July 7, 2009

St. Louis Cardinals manager Tony LaRussa and Twitter have settled their differences about a fake profile.

In court papers quietly filed last month, LaRussa agreed to drop his trademark infringement lawsuit against the site. The papers take the unusual step of specifying that Twitter didn't pay anything to LaRussa to convince him to dismiss the case.

The move comes several weeks after LaRussa prematurely announced a settlement. He told the press that Twitter had agreed to make a donation to an animal shelter charity to resolve the case -- which prompted Twitter co-founder Biz Stone to deny that the case had ended.

The fake profile page (now deleted) had three entries, all of which mocked LaRussa for his 2007 drunk driving arrest. One of the posts began: "Lost 2 out of 3, but we made it out of Chicago without one drunk driving incident," according his lawsuit. LaRussa argued in his lawsuit that the page caused him "significant emotional distress and damage to his reputation."

Some observers criticized the lawsuit, arguing that Twitter shouldn't be held responsible for pages created by users. But Web sites don't have the same types of strong legal protections against trademark infringement lawsuits as against other types of cases.

Web sites have immunity for libel lawsuits based on posts by users under the Communications Decency Act. And when users upload material that infringes on copyright, the Digital Millennium Copyright Act gives sites "safe harbor" provided they remove the material upon request.

But when sites like Twitter are accused of infringing on trademarks based on posts by users, there's no automatic immunity.

That's not to say that Twitter would have lost the lawsuit. Many people think that the company had a good argument that the page was a parody and protected by the First Amendment. Additionally, trademark infringement requires consumer confusion; it seems unlikely that people mistakenly believed the page was genuine.