Editors get geocoded again and again for each day they are
considered active.
So if the GeoIP gets updated, active editors with jump to a
different country from one day to the next.
So consider I edit 5 pages on enwiki on 2013-08-10 using an IP
address that's associated to Italy at that point in time.
On 2013-08-29 the IP->Country database gets updated, and that
previous IP is now marked as United States.
The scripts would count me active for United States from that day
on.
+------------+---------+---------------+
Date | Austria | United States |
+------------+---------+---------------+
2013-08-11 | * | |
2013-08-12 | * | |
... | * | |
2013-08-28 | * | |
2013-08-29 | * | |
2013-08-30 | * | |
... | * | |
2013-09-10 | * | |
+------------+---------+---------------+
Version: unspecified
Severity: normal