Just be careful if you go to edit the notes on a web page. For some reason, the web page limits the total number of characters and truncates any excess when saving. Apps can store much longer notes without any trouble via the API. An extra long note can be viewed on the web but don't try to edit it there or you will lose data.
I use the Cache Note on the cache page screen that shows Description, Hint, etc. The cache note two-way syncs to Geocaching.com with the Personal notes.