iComment

iComment makes it easy to add comments to web pages.

iComment is an add-on for Internet Explorer that allows you to add and read comments on any web page. Just visit a favorite site, start your own topic, respond to others' posts, or just read the opinions of others.

Comments appear as unobtrusive icons on the side edge of the browser; click to open their contents. They can be pinned to specific parts of the page, such as images or text. You can access the features via an icon on the browser toolbar. No registration is required - just choose a nickname (or remain anonymous) and you can comment anywhere. Comments are only visible with this add-on. A Firefox version is also available.