quashed a subpoena
... that an anonymous poster on a Yahoo! message board successfully quashed a subpoena to reveal his identity by claiming a First Amendment right to anonymous speech?
... that an anonymous poster on a <a href="./Yahoo!" id="mwB6o" rel="mw:WikiLink" title="Yahoo!">Yahoo!</a> message board successfully <b id="mwB6s"><a href="./Krinsky_v._Doe_6" id="mwB6w" rel="mw:WikiLink" title="Krinsky v. Doe 6">quashed a subpoena</a></b> to reveal his identity by claiming a <a href="./First_Amendment_to_the_United_States_Constitution" id="mwB60" rel="mw:WikiLink" title="First Amendment to the United States Constitution">First Amendment</a> right to anonymous speech?