Given <td class="fn n">, what is the meaning of "fn n"?

Sounds like fn and n are undefined style classes that don't get interpreted in the final web page since they are not defined in a CSS file.  Also, they can be used for identifying fields for validation purposes during scripting.  Let me know if this sounds correct.

That's correct. Basically if you don't find a css rule for those classes, chances are they are used for something other than css. I am not saying that "fn" and "n" are being used for validation in scripting. I am saying that in general you can use classes - whatever class names you want - in your markup to help/aid with your scripting.  If infact those classes are used in the context of microformats, than I could use the fact that fn stands for full name and potentially use that "knowledge" to validate the field to restrict it to letters, hyphens, spaces, and apostrophes.

Uping the point value.

Thanks to both of you guys.  I really appreciate a real world example in the explanation.  That is why hielo got the lion's share of the points.

Hielo, I would hire you in a minute. Take care.