No one.
More, people not only don't contribute, they don't even adhere to the guidelines that they themselves proposed. As a result I am more than just sceptical about such collaborative efforts, I'm now utterly cynical.
Note: I submitted the link, but I'm not the author.
Plot k against prediction accuracy (averaged over a number of runs). Look for a step, that is the correct setting of k. I don't believe there exists an algorithm for detecting that step as good as I can.
You can compare the cluster found by k-means run several times against what you get with a randomized version of your dataset though: http://blog.echen.me/2011/03/19/counting-clusters/
It's "tough luck" because the algorithms determining the number of clusters aren't magical. As with all machine learning, the results reflect the assumptions built into the algorithm.