@Mark_S
Interesting you say that. If we found a way to import their examples, which also includes javascript tiddlywiki would be a nice platform for study notes on what w3schools offers. If done right the value would be there and could fuel demand. Perhaps inspiring them to document learning tiddlywiki.
Speculation (I love doing this)
Normally one may think this impossible (incorporating standard javascript) with strict tiddlywiki/java integration requirements, but I have some ideas on this.
The Innerwiki plugin shows how one can generate a virtual tiddlywiki inside another (which you can save to a file if you want), imagine the same for virtual html pages constructed from the w3schools example code, and interact with inside an iframe. I believe this is already possible.
Similarly if we get a lot of flexibility from the file uploads plugin in development we may even be able to upload a virtual html page to the host, thus tiddlywiki can become a html publisher. Just imagine the automation to generate html pages we could design into tiddlywiki. Drag and drop site builders would be possible.