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 ?).
the BEST way to track pool performance is to track your individual earnings. you must have enough hash to get paid every day, and you must have a stable rig that isnt fluctuating a lot (like a lot of downtime).
you cant just take the total BTC balance, because 1, that itsnt accounting for the fees skimmed off by the pool owner, and 2, yes, there is a significant amount of BTC left over every day from small miners that werent paid (50-100 BTC worth). without an accurate way to see that carry over, you can only guestimate the amount (unless you happen to see it RIGHT after payout).
so tracking personal earnings of a stable rig is better since it will go back to zero after each payout.
you also should be taking into account the exact payout times (and hence, exact time between payout) and not just saying, "i got paid on monday, and then tuesday, thats 1 day!", when in reality you got paid at 2am monday and 4am tuesday, which is slightly longer than 1 day.
a lot of people over simplify things, make too many assumptions, and come up with incorrect, or padded, BTC/MH figures