As of January 2005, BitTorrent traffic made up more than a third of total residential internet traffic,<ref>{{cite web|url=https://www.wired.com/wired/archive/13.01/bittorrent.html|title=The Bittorrent Effect|publisher=Wired|date=2007-05-30}}</ref> although this dropped to less than 20% as of 2009.<ref>{{cite web|url=http://www.sandvine.com/downloads/documents/2009%20Global%20Broadband%20Phenomena%20-%20Executive%20Summary.pdf|title=2009 Global Broadband Phenomena|publisher=Sandvine.com|date=2009-11-16|url-status=dead|archiveurl=https://web.archive.org/web/20091122162729/http://www.sandvine.com/downloads/documents/2009%20Global%20Broadband%20Phenomena%20-%20Executive%20Summary.pdf|archivedate=2009-11-22|df=}}</ref> Some ISPs deal with this traffic by increasing their capacity whilst others use specialised systems to slow peer-to-peer traffic to cut costs. Obfuscation and encryption make traffic harder to detect and therefore harder to throttle. These systems were designed initially to provide [[anonymity]] or [[confidentiality]], but became required in countries where [[Internet Service Providers]] were granted the power to throttle BitTorrent users and even ban those they believed were guilty of illegal file sharing.
