Google Sidewiki is a free browser tool that allows you to add simple comments to any web page without having to leave the page. Sidewiki is less a wiki and more a commenting tool.

Google Sidewiki works with the Google Toolbar, so you'll have to download the toolbar (also free) from Google to use it. Google Toolbar requires Firefox or Internet Explorer. Safari users can use the Sidewiki bookmarklet to contribute comments. To make Sidewiki appear, just click on the Sidewiki button in the Google Toolbar. It opens on the left side of your screen, with comments listed in a vertical column. Type your comments into the text field and then click the publish button to make them appear in the list.

Instructors may find Sidewiki useful for facilitating discussions around topics covered on different web pages. They could also use it to list questions or draw students attention to information provided by others. Google touts it as a tool for enriching web pages with user's helpful tips, background information or expert insights.