I always wondered why Japanese people sometimes add strange suffixes to names or surnames. And I wonder why I had to go to Yahoo! to find the (hopefully correct) answer:
Keep in mind that a Japanese speaker may not be entirely sure which is your given
name and which is your surname. -san can be attached to either. You should use the
Japanese person's surname unless you come to consider that person a friend. -san
doesn't really "mean" anything. It is a suffix attached to a person's name to
indicate respect, roughly like "Mr./Mrs/Miss" -- but not quite. There are other
suffixes for other occasions and people: -sama for very important people, -kun
for close male friends, -chan for kids and people you want to be very familiar with.