Paul Walsh poses an interesting question on the Segala blog when he asks are Microformats perfect tools for spammers?
Machine readable contact details using the hCard format, for example, potentially make it very easy for spammers to automate harvesting of info to populate their databases.
I have already made it very easy for spammers by including my email address on this site and consequently I do get a lot of spam.
I don’t know enough about microformats to comment on this.
UPDATE: I see Paul is giving away free dinners at one of his restaurants in Dublin for anyone who happens along. This may be a chance to educate him on Microformats and get some free food while you are at it.