Goal keepers track the number of unique holders for a collection.
Choosing a goalkeeper is a big decision. Goalkeepers are the last line of defense for your squad. They are also the only critters that can hold the ball.
In general, having more owners indicates a healthy project. If the number of owners drops dramatically it might mean fewer people are interested in or believe in the project. Collections with a small number of holders have a smaller community and are more susceptible to manipulation. If the number of holders increases from last week to this week, your goal keeper scores points.
To convert the change in number of owners to points we want to calculate the difference between the number of owners this week and the number of owners last week and determine the rate of movement from the previous week (growth or contraction).
(Number of owners current week - Number of owners previous week) / Number of owners previous week
Imagine there are 10,000 items in a collection and 6,500 owners. On a week-over-week basis, the number of owners will change:
May 1: 6500 unique owners
May 8: 6535 unique owners
May 15: 6505 unique owners
May 22: 6570 unique owners
In this scenario, we can calculate the rate of change:
May 8: (6535 - 6500) / 6500 = 0.005384
May 15: (6505 - 6535) / 6535 = -0.004590
May 22: (6570 - 6505) / 6505 = 0.009992
To convert the owners rate change to points we can simply take the rate, multiply it by the total number of items in the collection, and round the result. This would mean that in the above example, the points would be (before any multipliers):
May 8: 54
May 15: -46
May 22: 100
This is great when the project is healthy, but it is very likely that some projects will run negative. Every critter starts at 100 points so the final value would be:
May 15: 100 - 46 = 54
We don't let the total points go below 0.