It could be that they have to get in the paperwork before the 31st so it can be manually processed. So the last day to them would be a day or two before. Also the beginning of the month makes sense because you'd want to dole out a bunch in the first week so you could coast a little in the middle.
That was my first thought, but then I think we'd see a larger drop on the 30th as well, since that's the last day of the month sometimes too. Someone suggested doing a graph with "days until end of month" on the X-axis, which might be interesting.
I think about this a lot. Not just for my personal accounts but then add in the pages and micro-brands one has to manage if you have a small business, or a band, or just a blog you have an identity for. It becomes a juggling mess.
Ha, lets have an master service that manages user-created services on these platforms. Then let Twitter play wack-a-mole with that...
