I would consider Internote the "Post-Its(tm) for the Internet."
When you install the extension, it places a yellow note on the status bar of your browser. When you click on it, a blank note fades in for you to move anywhere on the web page. If you browse to another page, the note (or notes) will still be there for later.
A possible enhancement for the future would be a collaborative effort with the Internotes. If Dave in Development wrote a web site and wanted Bob in Accounting to look at all of the changes, Bob could attach Internotes to it and let Dave look at the changes.
If you are a someone who uses Post-Its(tm) and are a power surfer, you could attach these to your main portal as to-dos for later, since they attach themselves to individual web pages.
Overall, this extension works like a champ. I would recommend this extension for you Post-It nuts out there. :-)