If you develop anything for the web, or even if you're just a user at the geeky end of the user scale you should read Adam Rifkin's aggregated take on weblications, Link's from that post will keep you busy for a long time. Of particular interest The Web Way, because it links to so many other cool places. Of more particular interest, this presentation on 'the lowercase semantic web' which is a new moniker to describe all those metadata enhancements that are gaining popularity because of the popularity of blogging. Blogging has created a market for smarter clients (sometimes just neat plugins for firefox or similar) able to extract useful data from DHTML, meta tags and link rel attributes and that in turn breeds these kinds of new micro standards.
You probably want to read this before enjoying the etech slide show.
Actually, what all this metadata tells me is that all of the new competing "closed source but free" desktop search engines coming out from all the "We're the platform"-contenders are failures in the making. There's so much metadata in the web you browse everyday and none of the desktop tools are ready to aggregate that metadata for you in a useful way. Nor will they ever be.
The possibilities in from-the-ground-up popular adoption of these new embedded metadata standards means that we need search that is also from the ground up, open and with a plugin architecture. There may be room for the homegrown information assistant, that I put on hold when I installed desktop google, yet.

Obviously the security fine print we need for plugins that work on the pages we browse is a little more involved than the security model we need on the data we're publishing on the web anyway. It may just be so involved that it's unfixable. But obviously, write now I am already trusting a vendor. I have yet to hear of MT plugins made by evil wrongdoers that trash your webserver instead of doing something useful, by the way.