Hi TW-ers,
I like to highlight when I read to call out the important parts of a document to myself. This helps me put my spin on it (and lets me do progressive summarization on those highlights later).
Over the weekend, I wrote a small userscript (which you can use in your browser with Greasemonkey, Userscripts for Safari, etc.) to be able to highlight webpages. Once enabled, you can click and drag to highlight on a page like you might do normally. When you’re finished, click the “download” button in the menu in the bottom left of the page. A .json tiddler is downloaded with your highlights, complete with the url field filled out for the URL that you were highlighting.
Anyways - you might find this useful! You can find the userscript on my website: http://peterhajas.com/highlight.js. Note that no warranty is implied or expressed - use this userscript at your own risk 
.