That's probably the day the article will appear in the print. It's very common practice among websites of print publications, so that there's no discrepancy in dates between the online and print editions.
Close. Yes, they keep the same date, but the common use of the date is the _last_ day it should be available for sale, so the day before the next issue is out. This lets bookstores and newsstands throw out everything with a date before today, no matter the frequency of publication. For weekly magazines, it is thus six days in the future. Monthly magazine need give only the month, and that does correspond to when it should be sold.
