Reports are circulating today that Pakistan's central telecommunications authority (PTA) ordered ISPs to block access to Youtube on Friday.
According to an official notification sent out by the PTA to major ISPs, the ban was supposed to be imposed on a specific URL, featuring a 04:58-minute-long trailer from Dutch politician Geert Wilders' controversial anti-Islam movie. The video had been uploaded to the website on January 28, 2008, and had remained largely unnoticed by the internet-savvy community in Pakistan.
Link to a regional news report, Reporters Without Borders has more.