http://atombox.net
The concept: Atombox is a web app for keeping track of small bits of text. An atom is less than 256 characters and a category is just like a folder (i.e., an atom can belong to only one category). You can view all atoms in a specific category or search for atoms across all categories. It's analogous to physical index cards held in folders, with the advantage of everything being searchable and in one place.
There's a keyboard shortcut for almost everything and we use SSL for all traffic to and from the service. We also have an "RESTful" API.
Currently Atombox costs $5.00 after a 30 day trial.
There are many rough edges, especially on the landing page. Any thoughts, suggestions, ideas are appreciated.
I'll be chatting at http://tinychat.com/atombox and we're @contextlines on Twitter.
Thanks!