While I'm sure this isn't the real reason, I could see that the accounting and check-cutting for 1 million organizations will have an noticeable impact on the a

While I'm sure this isn't the real reason, I could see that the accounting and check-cutting for 1 million organizations will have an noticeable impact on the amounts they're giving to each organization, especially the ones that get almost nothing. Others have already suggested cutting the list of charities down to a manageable number, perhaps from the list of charities that got the most interest already. I suspect this would end up producing bad PR from their curated list, so they've decided to just pick a handful and be done. But again, I suspect there was more to this and we'll never know the real reason.