As of October 2008, the plan includes two blocklists, the first used to filter "illegal" content, and the second used to filter additional content unsuitable for children. The first filter will be mandatory for all users of the Internet, while the second filter allows opting out. The government will not release details of the content on either list, but has stated that the mandatory filter would include at least 10,000 sites, and include both the ACMA blocklist and UK's Internet Watch Foundation (IWF) blocklist. In December 2008 the IWF list caused problems when the Wikipedia article Virgin Killer was added to the list, as it prevented many people in the UK from being able to edit Wikipedia.