Facebook says it is having success using its artificial intelligence to delete terrorism-related posts, though more work is still needed. At present, roughly 99% of material Facebook removes because of links to Al Qaeda or the Islamic State is first detected by its automated filtering system rather than by users. But founder Mark Zuckerberg cautioned that it would take "many years" to fully develop the required systems to remove all terrorism-related posts, as there are many more groups that post such harmful material on the site.