The concept is people sign a pledge to donate an
amount to Wikimedia either
every month, every quarter, bi-annually or annually. For example, someone
pledges $5 per month to support the Foundation. They fill in details on a
form and every month the Foundation sends them a polite reminder with a
quick link to the donate page with the amount filled in.
That could work. I think it is important that we try and move away
from discrete fundraisers and try and get donations year round, and
voluntary reminders to donate could work well.