I'm definitely a fan of the concept of semantic web, the ability to reach individual pieces of data you want from the internet rather than having to get whole pages and then find the information. A little while back, I wrote about FOAF (Friend-of-a-Friend), a semantic web tool to make social connections more readily accessible from the internet.
Now, I'm starting to get enthusiastic about Microformats, little bits of code you can add to a website or page that humans don't see, but make some particular type of information accessible to the web. If you want customers or potential customers to be able to get to contact information, calendar information (events, possibly business hours), or product information without having to read whole pages, there's a little set of tags you can stick into your page code that will make it possible. Yahoo! search recently announced support for some of these formats (seems to be calendars and reviews but not yet product listings) so people performing search will get the information in response to their Yahoo! search. These are particularly great because you need very little technical skill. The examples springing up around the web are things you can cut and paste into your web code even if you only know a little bit about html. And, there are programs, like hCalendarCreator, that will create the code for you. You can use this code even if you're on a pre-fabricated site that only lets you enter text and html in a module on a page.
The only downsides I can see are: 1) each microformat has a limited purpose and a limited number of things you can express and 2) some have questioned how long they'll be supported. The answers to both these challenges appears to be, ultimately, RDF which is the more robust smantic web standard sanctioned by the World Wide Web Consortuim. RDF will pretty much let you express anything about anything (solving problem 1). RDF requires a much higher level of technical skill and access to the header portion of your web pages. But, there's a next generation of tools (things like GRDDL) coming that will translate microformats to RDF, so even if Yahoo! does decide to pull support for every microformat you'll have a way to still get your tags read (solving problem 2).
I'll be trying this technology out on a new e-commerce site and will report back about the experience.