ChromeNote

ChromeNote syncs with Simplenote and also keeps a local copy so you can work offline, syncing when you're once again connected. Notes can be created, modified, deleted, and pinned. The only major feature missing is tags. (Pinning and searching are implemented.) Settings allow you to change the font, note colors, and syncing frequency. When you run the app for the first time, or any time you haven't entered your Simplenote credentials, you're prompted to enter them. All you need to use ChromeNote is a free Simplenote account from simplenote.com; it's not necessary to use any Simplenote apps.

Screenshots from Chrome Web Store