FloatNotes is a simple Firefox Add-on that allows you to add notes to any website.
FloatNotes supports Markdown syntax. This makes it very easy to apply basic formatting to your notes. It even lets you add links and images.
Read more about the basic syntax.
Notes can be minimized so that they don’t take up much space. They automatically expand and minimize again if you hover over them.
You can specify if a note should only appear on one page, its subpages or on the whole website. You can even make a note appear on all webpages.
FloatNotes integrates with Firefox Sync to securely synchronize your notes between your computers. Firefox Sync is built into Firefox 4 and available as add-on for Firefox 3.6.
Attach notes to the window, so that they do not scroll with the page but stay at the very same spot in your window.
It can be difficult to remember whether there are notes further
down the page or not. With small indicators, FloatNotes shows how many notes are below or above the current view and you can jump directly to a note.