My understanding is that CEA exists in order to simplify the paperwork of multiple projects. For example, Effective Animal Activism is not its own charity; instead, you donate to CEA and transfer the money to EAA. As bryjnar said, there's not really any overhead in doing this. Using CEA as an umbrella much simpler than trying to get 501(c)(3) status for EAA on its own, which would be painstaking process.
I am disappointed that my realistic and fact based observation generated a down vote.
At the risk of an additional down vote, but in the interest of transparent honest exchange, I am pointing out a verifiable fact, however unsavory it may be interpreted.
If over time the time cost of intermediaries (additional handling and overhead costs) remains below the cost of the steps to eliminate intermediaries (the investment required to establish a 501(c)(3)) then I stand corrected. While an improbable situation, it could well be possible.
Both GiveWell and the Centre for Effective Altruism (CEA) --an Oxford-based umbrella organization consisting of Giving What We Can, 80,000 Hours, The Life You Can Save, and Effective Animal Activism-- have been discussed here before. So I thought some folks might want to know that these organizations are recruiting for a number of positions. Here are relevant excerpts from the official job announcements:
(Full disclosure: I'm friends with the co-founders of CEA and have donated to Effective Animal Activism.)