I've been trying to get some stats for the Windows 8 challenge over on Super User. I've noticed that there are some questions missing if I add fromdate=0. Why is this?
Without fromdate:
http://api.stackexchange.com/2.1/questions?site=superuser&tagged=windows-8&filter=total
{"total":807}
fromdate=0:
http://api.stackexchange.com/2.1/questions?site=superuser&tagged=windows-8&filter=total&fromdate=0
{"total":764}
fromdate=1970-01-01:
{"total":764}
When comparing the two sets, it seems that fromdate excludes questions with a negative score (score < 0). Is my guess correct? Why? Is this documented anywhere? Can intentionally I include questions with a negative score when filtering with fromdate?