The Dublin Core and Microformats

I understand the benefits of your site utilizing these features but I see a lot of sites don't. Can anyone tell me why?

I cannot say anything about Microformats, but Dublin Core is a XML based description file that should ease up content search and classification in digital archives. This initiative was started in early '00s, but I have yet to see its widespread usage (as with all stuff that hasn't come to life in such a long time, it probably won't happen at all).
In any case, avoid, it's not worth any effort.

Not worth it really. Micro Formats appear to help you rank Geo for local areas, although the boost doesn't seem to be anythng special as i have implimented it myself and not really noticed change. It is all early days for this sort of stuff yet i think. And many people are over emphasising its usage. I don't think it can hurt to micro format addresses etc but i wouldn't bother with that dublin core clap trap.