Documenting previous attempts at formats is a key step in the microformats The microformats process.
Here are some sources of previous formats that you should consider in your research.
other standards bodies
Participants in other standards bodies of have already spent many years in committees arguing about and developing their schemas. Better to leverage all the hard work that others have done before you, than to go off as a solo cowboy inventor, and waste time repeating all their mistakes. It's also much easier to start from a well established schema, and map into into semantic HTML than to develop a new schema.
It's quite possible during this step that you'll find someone else who has dealt with the problem(s) you're addressing. Perhaps even solved it/them. Do your best to open a dialog with others who have encountered the same problem(s).
Regarding standards bodies in particular, we want to build connections with existing successful communities - we want people to work together in the open to develop a good solution which will cover the majority of cases.
Here are a few other standards bodies and previous formats.
- HTML - used as the basis / foundation for microformats
- W3C note on dates and times - also used for dates and times
- IETF - IETF has developed many formats (often in pre-web contexts) that have potential for re-use, e.g.
- vCard specifications - vCard RFC 2426 - used in the design of hCard 1.0
- iCalendar RFC 2445 - iCalendar RFC 2445 - used in the design of hCalendar 1.0
- rfc-4287 - rfc-4287 - used in the design of hAtom 0.1
- impp - RFC4770 - feature being incorporated into hCard 1.1
- iCal Basic - RFC5445 features being incorporated into simplifying hCalendar
- vcard4 - vCard 4 RFC 6350 features being incorporated into hCard 1.1
Often domain-specific communities will emerge that work on and develop an open vocabulary for their own purposes. It's worth searching for these, or at least searching for them, and here are a few pointers to search pages etc. that may help:
vendor oligopoly proposals
Sometimes there are format proposals and attempts by a small number of companies working together in a non-necessarily open fashion (often in a "delayed open" way). Despite potentially suboptimal methods, such attempts should still be documented as previous formats.
vendor specific proposals
Frequently vendors will propose their own standards or APIs for developers to adopt. We should look at them as well, especially if they license them with open standards licenses.
- OGP - by Facebook, licensed using Open Web Foundation Agreement.