Aha, thanks for the explanation. But why the initial payout contained a lot of address? Just because those addresses are in the queue, which is shared between p2pool nodes? By the other words, it is possible that my address will be in this list for something other who decided to bring up the p2pool node?
When any p2pool node finds a block, everyone in the share chain gets paid. Once you find nodes (of your own, or a fee % of the shares your miners find) then you'll be in the share chain for while. You'll be paid on every block found by anyone on p2pool until your shares expire.