There are a number of websites that let you tag people in photos, such as Facebook and now flickr, but is there an EXIF standard for tagging who is in a photo, and where they are?
Adobe's XMP metadata standard supports information defined by the Metadata Working Group (MWG), which includes a definition of how to store face tagged data. See:
So while this isn't "EXIF" per se, it is metadata stored in the image. I'm just starting now to explore how widely supported this is.
There is not. IPTC, another image metadata standard, also does not contain a "People" field. There's a Contact field, but that is used for contact information for the photographer.
Most people I know will store people as keywords. The main debate is whether or not to include spaces (would a photo of me be tagged as aaronhockley or as "aaron hockley"?). I don't use spaces since that simplifies things at times, but it's pretty subjective. I think the main thing is consistency... pick one method and stick to it.
I don't think there is ... you can take a look at the EXIF specifications at http://www.exif.org or http://www.jeita.or.jp/cgi-bin/standard_e/pdfpage.cgi?jk_n=47
EXIF is a technical standard for images files ... not the content / subject of the image.
The MetaDataWorking Group, section 5.9 (face regions), is the best standard going forward for managing people tags. Right now Picasa, MS Photo Gallery and Fotobounce support this standard. Hopefully Adobe will jump on board since they are on the committee for this standard...
The only metadata field to store the people inside the file as metadata at the moment (according to MWG and XMP standards) is XMP:Iptc4xmpExt:PersonInImage
MWG also assumes to describe and store people faces as Randy said above.