Web buttons, button graphics, badges or stickers are pictures in some World Wide Web pages which are typically used to advertise programs that were used to create or host the site (for example, MediaWiki sites often have a "Powered by Mediawiki" button on the bottom right corner of the page), programs that are recommended to view the site, or that the site passes W3C HTML validation. The buttons are linked to the advertised sites. These were first popularized by Netscape and Microsoft during the browser wars.