Just like WebSockets really, you can feel the obvious potential but I have yet to encounter a good example of how Web Workers will help the average web developer to solve his problems in a more efficient or elegant manner.
The fact that they can't manipulate the DOM in a simple way is probably one of the reasons why they haven't crossed the mainstream line. That or the still approximative support across browsers.
Or maybe it's just that they're too much of a game changer and we've yet to wrap our heads around their power. I don't know...
I happen to know this because I was starting to use web workers about 6 hours ago. And yes, html5rocks does include the blob trick.
Even without the context of minification, I like your use of Blobs to instantiate a Web Worker.
