Books and other documents may often include pages intentionally left blank stating "This page [is] intentionally left blank." As explained in the Wikipedia intentionally blank page article, this is often done due to the way pages are printed from a much larger sheet of paper or for legal reasons. On the web you can find an online equivalent in The This Page Intentionally Left Blank (TPILB) Project which notes:
In former times printed manuals had some blank pages, usually with the remark “this page intentionally left blank”. In most cases there had been technical reasons for that. Today almost all blank pages disappeared and if some still exist here and there, they present flatterly comments like “for your notes” instead of the real truth: This page intentionally left blank!
Nowadays the “This Page Intentionally Left Blank”-Project (TPILB-Project) tries to introduce these blank pages to the Web again. One reason is to keep alive the remembrance of these famous historical blank pages. But it is the primary reason to offer internet wanderers a place of quietness and simplicity on the overcrowded World Wide Web—a blank page for relaxing the restless mind.
Since I sometimes want to take browser screenshots that display options that are available in various browsers, but would prefer not to have any webpage content displayed in those screenshots, I've also created a this page intentionally left blank" page.