PHILADELPHIA- Software filters work much better than a 1998 federal law designed to keep pornography away from children on the Internet, a federal judge ruled Thursday in striking down the measure on free-speech grounds.

Senior U.S. District Judge Lowell Reed Jr. also said the Child Online Protection Act fails to address threats that have emerged since the law was written, including online predators on social-networking sites like News Corp.'s MySpace, because it targets only commercial Web publishers.

"Even defendant's own study shows that all but the worst performing (software) filters are far more effective than COPA would be at protecting children from sexually explicit material on the Web," said Reed, who presided over a monthlong trial in the fall.