Google Sidewiki is an online service from Google launched on September 23, 2009. Google Sidewiki is an extension for web browser. You have Sidewiki for Internet Explorer and Firefox through Google Toolbar. You have Sidewiki for Google Chrome browser through an add-on. You have Sidewiki for other browsers like Safari as a bookmarklet. When you visit a website with Google Sidewiki you can press on Sidewiki button. It opens a window where you can read others' comments or write your own comments. The owner of the website can not stop you from doing this.