Twitter posts like this one:
have a place- name and corresponding coordinates (indicated by the prefix “l:”). This has allowed them to be plotted on a map.
It should be possible for the poster to send, say:
We’re still deep in the Sundarbans, near Tambulbunia, meeting experts on dolphins and tigers. #hcard: fn+locality:Tambulbunia: country-name:Bangladesh: geo:22.27722,89.71905
using colons as delimiters and have Twitter render that comment marked up as an hCard.
In the short term, this could be achieved by a third-party site, like #hashtags .
UPDATE: being more mindful of the 140 character limit than I have in the above example, perhaps class names might be abbreviated (“loc” for “locality”, “ctry” for “country-name”, and so on).
Mabblog 
January 6, 2008 at 9:02 am
We are doing that in txioka.net. At txioka.net/ekitaldiak.php we are using twitter with nanoformats (http://microformats.org/wiki/twitternanoformats) to parse it like hCalendar microformat. At txioka.net/azoka.php we are doing the same with hListing. At the index we are using hAtom.
If you are interested consider your contribution in the wiki. Nanoformat extractor php class is ready to launch (GPL). If you are interested I can send you a copy to try it.
January 7, 2008 at 10:01 am
Interesting idea. Almost a micro/picoformat crossover?
I noticed Brian adding location to his twitter profile with @long;lat, although I realise @ is reserved in twitter notation for nick linking.
January 7, 2008 at 11:44 am
UPDATE: Looking at the hCard cheatsheet, it should be possible to abbreviate all the necessary hCard attributes to two letters, and still keep those abbreviations, meaningful e.g fn=fn (!), family-name=fa, adr=ad, latitude=”la” and so on.
May 1, 2009 at 11:28 am
[…] Une méthode suggérée pour publier des microformats dans les billets Twitter […]
June 8, 2009 at 10:20 am
Further discussion at microsyntax.pbworks.com/Geoslash.