I created a note-taking app which works in every* browser, with and without JS and CSS, has bookmarklets for clipping, PKI-backed user accounts, completely portable data format, threaded conversations, completely auditable data structure, labeling, queryable with SQLite, web of trust for the user identities, and support for adding and running code.

* Mosaic has issues, and I have not tested on many pre-Mosaic browsers. I've never tested with WorldWideWeb. I've done extensive testing with Netscape and IE. Older versions of Chrome are extremely flaky for some reason, and often don't even run. Most old and retro browsers work, however, including sessions, posting, voting, etc.