为什么TIME等外国杂志的实际出刊日期要远远早于杂志封面上的日期？

有个词叫cover date，一是因为不是所有的杂志都能立刻卖光，所以希望即使是杂志打折卖了，也让消费者有一种“当时的杂志”的感觉；二是为了让报刊亭的人知道什么时候可以把这些杂志下架，或者退给发行杂志的机构，或者销毁，所以cover date也叫pull date。

以下是来源wikipedia：

In the United States, Canada, and the United Kingdom, the standard practice is to display on magazine covers a date which is some weeks or months in the future from the actual publishing/release date. There are two reasons for this discrepancy: first, to allow magazines to continue appearing "current" to consumers even after they have been on sale for some time (since not all magazines will be sold immediately), and second, to inform newsstands when an unsold magazine can be removed from the stands and returned to the publisher or be destroyed (in this case, the cover date is also the pull date).

Weeklies (such as Time and Newsweek) are generally dated a week ahead. Monthlies (such as National Geographic Magazine) are generally dated a month ahead, and quarterlies are generally dated three months ahead.

In other countries, the cover date usually matches more closely the date of publication, and may indeed be identical where weekly magazines are concerned.

In all markets, it is rare for monthly magazines to indicate a particular day of the month: thus issues are dated May 2005, and so on, whereas weekly magazines may be dated 17 May 2005.