We set up a site some time ago to take advantage of Technocrati's microformat to vCard parser. Worked fine at the time, but not that its moved to a new server and become a weird, stripped back separate service, it no longer works. Instead it says "No hCards Detected" and leaves it at that. I think the hcard markup is okay, so what gives?
I suffered the same issue, my advice: Don't rely on the service, take a DIY philosophy.
Create a vCard and host it on your site for visitors to download (that fixes the issue and gives your visitors a direct method to access it) and keep the hCard as Firefox has some neat extensions which can take advantage of them like Operator and Tails Export - plus some social networks notice them.