As I've talked about before, Microformats are a clever and simple way of marking up your HTML so that both humans and machines can understand what you are saying.
(If you are interested, the last thing I wrote on Microformats was: Microformats Proposal for Reputation and Trust Metrics. That article doesn't really have anything to do with this article other than it's also about Microformats too. But if you're into Microformats you may find it a good read. But anyways,....)
One of the areas that has been lacking a Microformat (as far as I know) is the world of multimedia. (Although people have been putting thought into it.) This article deals with just one aspect of multimedia Microformats: linking. This article doesn't really try to invent any new Microformats, but encourages people to use existing HTML elements and attributes to communicate and specify semantics and metadata useful for linking to video and audio media.
One of the things we sometimes do when dealing with media (such as audio and video files or streams) is link to them. For example, here's some sample HTML markup doing just that:
Go and <a href="/movie/grad2005">watch this</a>.
However, this doesn't give us much semantics or metadata. What type of file (or stream) is at the end of that URL (specified in the href attribute). (Is it an MPEG movie‽ An AVI movie‽ Or an Ogg Theora movie‽)
(Note, the URL we have does NOT have a file name extension like .mpeg, .avi, or .ogg. Those from the Windows or DOS world are probably accustomed to them and may think that you need them to tell you the type of file [or stream] you are dealing with. However, that is NOT how it works on the Web. On the Web, a file's [or stream's] type is NOT specified by an extension; it is specified by with its content type. On the Web, extensions mean nothing; it's the content type that matters. But I'm digressing. Getting back to it....)
Also, what should we "call" that movie? (The words that the link is bound to is "watch this"; so should that be the title of the movie‽)