[bramstein]

Zooming is problematic, I haven't quite figured out a reliable way of fixing it yet. The problem is most apparent in Webkit based browsers, Firefox seems to handle it much better (though there are still some small problems--most can be fixed though.)

Yes, this is an application of dynamic programming. The computation is actually quite fast, most of the time is spent in retrieving the text metrics (put each word in a span, retrieve width and move on to the next word.) If that can somehow be alleviated it would become a feasible solution.

I agree with you that browsers should support this natively (Internet Explorer actually does.) If you are interested, I've written a bit on this subject in this Typophile thread: http://typophile.com/node/71247