Three or four years ago, I and a few others did a lot of work preparing a draft for a microformat for measurements, hMeasure, for marking up length, mass (weight), temperature and so on. Sadly, it has yet to be taken up by the unelected and unaccountable clique who oversee the microformats “process” — but that’s a story for another time.
Recently Corey Mwamba asked how he could semantically mark up the frequencies of radio stations, for example:
Heart FM (Sussex) 102.4 MHz (Eastbourne)
My friend Toby Inkster rightly proposed the use of the hCard microformat’s “note” property, but I think that authors could also usefully use a non-microformat class name of “frequency”, for added semantic richness (and to aid screen-scrapers), and better still, the proposed hMeasure:
<div class="vcard"> <b class="fn org">Heart FM (<span class="adr"> <span class="locality">Sussex</span> </span>) </b> <i class="note frequency"> <span class="hmeasure"> <span class="num">102.4</span> <span class="unit">MHz</span> </span> (<abbr title="50.9761;0.2293" class="geo"> Eastbourne </abbr>) </i> </div>
If enough people use this pattern (and write up their experiences of doing so), then a de facto microformat will emerge.
Update: There’s a copy of that code at pastebin.com/CXCYT5nF which has syntax highlighting, and which you can replicate and edit if you wish to make a counter suggestion.
Update 2: I have now implemented this in the Wikipedia Frequency template, as seen, for example, on the article about BRMB.