Simple note taking extension for ChromeChrotes was created after losing data too many times using "data:text/html, <html contenteditable>" as a Chrome bookmark.
Chrotes saves data to chrome.storage.sync, which means it will sync across devices. Each chrote is unique to a page (domain/sub-domain combination). To view & edit the chrote, click the extension icon while on the desired page.
You can view the source code on GitHub via the website link below.