There's been a few feats already, so I think it's a good idea to share here some of the information I've collected from them. You can find the graphs and stuff here: http://resources.grelca.com/feats/
The graph at the bottom for each feat is a histogram based on the the list of top players and their contributions such as this one. The y-axis is logarithmic, which means that two-times increase on the y-axis means a ten-times increase in contributions, though note that the y-axis does not start from zero. The donut chart shows the total amount contributed by each group of players. Both charts are grouped by the rock reward they get. The sidebar shows the goals for each feat and the reward per unit of contribution.
N.B. The data for the conch feat is corrupted and should not be taken as accurate. The goals and rewards for failed feats (the Call to Feast) and early feats is incomplete.
If you want to play around with the data, or fix a bug in the site, the source code and data for this page is available on GitHub.
Analysis
The graph is mostly straight, which is the distribution you'd expect from leaderboards like this, but at around the 120-200th player the graph suddenly turns into a curve, with the gradient increasing dramatically. The disparity is so large for some feats that the leader is contributing ten times the amount the 100th player contributes. This could be due to the pressure to stay on the top of the leaderboards.
On certain graphs you can see a kink in the graph in the boundary from blue to pink. The is the difference between large rocks and medium rocks, and more importantly, having your image immortalized on the leaderboards instead of just a name. The high visibility of this boundary most likely fosters additional competition for players at the margin. The boundary between pink and orange is not highlighted on the leaderboards at all, and this the graph is smoother.
One last interesting thing of note is the fact that the currant reward for the Questing and Contesting feat is 50 currants per contribution - exactly the price you pay for repeating the Gwendolyn quest. Coincidence? or did TS anticipate players repeating this quest?
Notice other interesting titbit about the graphs? Thoughts? Flaming bags of guano? Post them below!