If you've ever used the post-it notes in OS X's Dashboard app, you know how handy those little buggers can be.
But (as far as I know), you can't share those notes from computer to computer, and if you use a non-Mac OS, you can't use them at all.
Thankfully, Posti.ca has put together a web service that gives you the look and feel of Apple's Notes Widget but runs in your browser. Since creating an account is free, you can now sign up, create notes, and view them from any computer.
I've been using it to jot down ideas I have while at work that I need to follow up on at home. The service seems stable so far, though there are a few bugs they've yet to work out.