PPLNS means that when a block is found, the block reward is shared among the last N shares that miners sent to the pool, up to when the block was found. The N value the pool uses is 3 days.
How much of each block does the pool reward?
Transaction fees are included in the miner reward. Pool fee is 0.9% of the total.
When are payments sent out?
The block 'Status' must first reach '+101 Confirms' on the Blocks page, and then is flagged as 'Matured', before the reward is distributed. The block reward transaction is created manually some time before the block matures, and sent out automatically a minute after the block matures.
The payout may use a zero fee transaction, so we will confirm it with the next block we find after the transaction is sent out if it isn't confirmed before that by some other network block. You may not see the transaction in your wallet before the first confirm.
What's a shift? When your miner sends shares to the pool, the shares are not stored individually, but rather summarised into shifts. Shifts average ~50 minutes in length. Aproximately every 30s, the pool generates new work and sends that to all the miners. The pool also sends new work every time a block is found on the Bitcoin network. A shift summarises all the shares submitted to the pool for 100 work changes. However, when we find pool blocks, the current shift ends at the work in which the block was found and a new shift starts. A pool restart will also end the current shift and start a new shift. A network difficulty change will also end the current shift and start a new shift.