MyStickies, a web-based application created by Jacob Wright and Derek Andriesian, gives you the ability to put a sticky note on any web page your browser can visit. When you come back to the page, your sticky note is still there, where you left it. This enables us to remember what was important about the page to us.
A part of the MyStickies service is an account area where you can go to quickly view all the notes you have placed. You can modify the text of the notes from there or delete old notes no longer needed. The account allows you to review your notes, go back to the sites you have "stickied," and otherwise manage your notes.
Lables are an extremely useful way of organizing your stuff. The basic idea is that you can add any number of descriptive labels to a note and then view notes by those labels later. To add a label to a note you just click on the note to select it, then either press TAB or click on the yellow nub on the right side of the note.
MyStickies currently is planning and has in the works support for multilingual notes, browser extensions for Internet Explorer and Safari, sharing tags' notes and individual notes with friends, rich text notes (bold, italics, and links) and some form of public notes.