Cool, it would be great if they could sustain exponential growth! I imagine this may happen from people getting into these ideas and then telling their friends, who tell their friends, who tell their friends, and so on. That seems a good hypothesis to explain the exponential trend.
Does GWWC know how many of these members would have been donating significant sums without GWWC? Presumably they share this information with donors? I realise this is hard to work out, as people who are interested in these ideas would likely have come across GiveWell and EA at some point anyway.
I would be interested to hear whether readers do or don’t consider doing this.