Currently its not possible to control how external data is parsed in unless its formated into some sort of EQ2 XML format. If its HTML, the HTML window displays it, but it can't be manipulated. If its some other format, the best you'll get is a straight text display of the source.
Soon as I work out a few bugs with my current sets, I'm gonna be experimenting with some of the other database related UI elements as well as trying a few more tricks to get links working in the browser.
If I can get the other database objects working, it might be possible to use an auto-updater to pull down XML files formatted with a known database format and display it ala Journal.
In any event, its already possible to set your guild site up with a Comments/Notes section that includes a plain HTML view that would display in the HTML window
You'd have to use a real browser to add/change comments/notes, but anyone with the URL could read them in-game.