I just noticed on the main graph that the total BTC (all users) does not go back to 0 at the end of the pay day, even far from it (~ 80-90 BTC maybe). I actually looked at that graph the last few days and that's why I decided to mine again at MC, thinking the pool was getting at least 0.01 BTC/(Mh/s)/day (170-200 BTC/day for ~14000Mh/s). It seems that I actually got much less than that the last 12 hours; I probably made a mistake in estimating the perfs per day by not paying attention to the initial BTC at the beginning of the day.

So I first thought there was a bug with the graph, and then I though: do all these BTC not being paid every day come from many users with very small balance? I know I've had one for a few days. I guess you'd need quite a few users with a balance less than 0.01 BTC (~8000 ?).