WikiLeaks soldier's court-martial wrestles online evidence rules WASHINGTON (Reuters) - The trial of a U.S. soldier accused of providing classified materials to WikiLeaks is unique for the size of the leak and also faces the unresolved cyber-age issue of whether Tweets and Web pages can be admitted as evidence. Judge Colonel Denise Lind was left to wrestle with this question when the court-martial of Private First Class Bradley Manning, who is accused of the largest leak of classified material in U.S. history, last convened a week ago. Manning's attorneys had argued that Twitter postings offered by prosecutors did not meet evidence standards. When the trial resumes on Wednesday, it will take up the issue, which is sufficiently thorny that the U.S. federal court system's Advisory Committee on Evidence Rules is to meet in October to weigh whether its rules should be changed to take into account technological advances in how evidence is preserved and presented. "It's definitely a brave new world where they (courts) don't know how those old standards apply to new technology," said Colin Miller, an associate law professor at the University of South Carolina. It is a problem that courts cannot escape, as evidence from social media and other online postings is increasingly playing a role in court cases. A study last year by X1 Discovery, an online search firm, showed that evidence from social networking sites played a significant role in almost 700 state and federal cases over a two-year period. Jeffrey Bellin, a professor at William and Mary Law School, said the Internet and the explosion in social media such as Twitter and Facebook were an underutilized resource since they offered material that was "frozen in time." "We might not be harnessing the full value out of what is out there on the Internet," said Bellin, who backs easing hearsay evidence rules for some Internet material. Manning's lawyers argued at the court in Fort Meade, Maryland last week that Twitter postings and an archived WikiLeaks page offered as evidence by prosecutors were invalid since the prosecution had accessed them indirectly through Google rather than directly through Twitter or WikiLeaks. The judge put off ruling on the matter. Miller and other law professors said evidence rules had remained unchanged even as online technology advanced. Judges still have to decide whether evidence is authentic and whether to admit hearsay - a statement made out of court offered as evidence. U.S. courts have given different interpretations about what makes electronic material authentic. It's generally ... not enough to offer a printout of a Tweet. Usually you need more than that because it's so easy to manufacture that kind of stuff," said Stephen Saltzburg, a law professor at George Washington University. Courts often turn to experts or online firms to certify evidence as authentic. In 2009, a New York district attorney subpoenaed Facebook Inc records to verify a teenager's alibi that he was updating his Facebook page when a robbery took place. Facebook itself has a site - Law Enforcement Online Requests - for police seeking account records. Reporting by Ian Simpson; Editing by Scott Malone and David Brunnstrom