Giving What We Can recently celebrated its 5th birthday. It's not much of a party if no-one external congratulates you, so here we go: Happy Birthday, GWWC!
It's pretty impressive how much GWWC has grown since those early days. Here's a chart of total membership, which I've put together from GWWC emails and liberal use of the internet archive. I'm sure they have better data (without gaps!) internally, but I've never seen this chart before. Notably, growth seems to have picked up since the fall of 2013. Did GWWC change their strategy at that point? (or their membership-counting-methodology?)
Putting the same chart on a log scale, we can see that GWWC have actually done a reasonably good job of sustaining exponential growth.
Fitting a line of best fit to the chart, I estimate GWWC's membership is growing 73.1% a year. Assuming 2% population growth, it will take just 30.25 years before all the world's population are GWWC members. Taking over the world by the time I'm 58 sounds like pretty good going!
Happy Birthday, Giving What We Can!
edit: formatting of links