Project Gutenberg sets a production target for itself. The idea is that we try to produce X texts in a month, and in books before #10,000, we dated the texts according to what month of our schedule they appear in. For example, if our target for September 2000 was 50 texts, and we actually produced 55, then the last five would be dated October 2000, and we'd get a head-start on the month. At the time of writing the original FAQ, in July 2002, that target was the publication of 200 books per month. However, our actual production far outpaced our targets, with the result that the "head-start" had accumulated so much that in July 2002, we were releasing books scheduled for March, 2004!
The fact that we were so far ahead of schedule makes this quite confusing for newcomers. If it bothers you, just don't think about it! But at least it's better than being behind schedule. We didn't always produce so many books. In the September 1994 newsletter, Michael Hart wrote:
As always, I am terrified of the prospect of doubling our output to 16 Etexts per month for next year, we really need your help!!!
That was when the Project's target was 8 Etexts per month. Today, our target is heading towards 12 eBooks per day!
In books after number 10,000, we abandoned the "Schedule Month, Year" idea, and the "Release Date" is the actual date on which we posted them.