Test banners are run through the year - small audiences, particular countries or whatever. (Wikimedia Fundraising A/B-test the heck out of everything they do.)

Test banners are run through the year - small audiences, particular countries or whatever. (Wikimedia Fundraising A/B-test the heck out of everything they do.) But the big fundraiser is the annual one, around Nov/Dec, in which they go all-out to raise this year's target as quickly as possible.