I have seen references before to the tag and like all beginners did not look into it as it is clear isn't it? You use it to create addresses. Well this is the web and the W3C and not everything is what it seems.
Here are two authorities on the subject:
Note: The tag should NOT be used as describing a postal address, unless it is a part of the contact information.
For me this is fairly clear, but not what I thought as a beginner. The address tag is not for addresses, it is for contact information about the author. If I post this in an ezine for instance, the author information about me with my email and or URL would be the address. I am the contact person and not the newsletter that posts this. KillerSites is not the contact when I post it on their forum. If you have questions, you contact me.
So if you use it for a street or postal address you are clearly wrong.
Or are you?
In a comment section at a SimpleBits' SimpleQuiz from 2004 , some very good comments are to be found (126 in all, but good reading). It became and issue of how best to markup physical addresses and rather than people saying A, B, C or D, may began tweaking the offered solutions.
Comments here are long closed, I was dismayed that it took almost half the comments before someone pointed out the semantics of Address as many were stating simply "A is correct because that is what the tag is there for." Well no, no it isn't, read the specs. It is the contact information on the author. So name, email, URL and such.
Some posters blatantly ignore this but towards the bottom more and more reference it and some begin to point out other ways of seeing it than what I know to be the meaning of Address.
Now the easy to understand has become vague indeed. Let us look again, this time with my highlights:
Are you seeing what I missed and others saw?
Once again by generously using their favorite word, "may," the W3C's use of it opens the definition to be used and abused in many ways aside from it?s intended use.
Also look at it from a corporate point of view. We looked earlier at me as the author. Now let's say it is a page on a corporate web site. Who is the "contact information for a document or a major part of a document?"
It depends, but it would be either a division or department or the corporation as a whole. So if I have a question or issue with the content who is my contact person? Likely the Public Affairs people for the corporation. How would I contact them? URL and email of course as before, but I may wish to send a letter. Now suddenly a postal address or street address I can visit to speak to someone in person is now fitting snuggly in the definition, especially with that "may" thrown in. A local part of a nationwide chain would not be the owner so the corporate headquarters would be the owner.
Personally, I find that stretching it as this tag is really meant to be directly on each page. So I do not agree with the full address use of the tag, To use it on one page to represent ownership and responsibility for an entire site is not in the spec. The spec clearly states it is "for a document or a major part of a document," meaning singular, as under this theory you need to place the physical address of the company on every page. But I must admit that I can not hotly dispute it because in theory, even stretched theory they are partly right at least and you can liken a web site to a document, like a brochure of many pages.
Another repeated argument is that telephone numbers should not be included, they are not part of the address (usually meaning physical address), but they are however "contact information for a document or a major part of a document" and by that definition better candidates for the address tag than a complete physical or postal address.
So the tag turns out to be not so simple after all. Like a Mirror you identify way off, when you take a closer look it is a funhouse mirror and depending on what angle you look at the specs for address. It means different things to different people and warps to be seen however you wish to use it like a funhouse mirror warping your reflection depending on the angle you see it. With W3C specs, things are not always what they seem.