Thanks for your response!
For an LTC-based altcoin, I observe that many coingen transactions pay to 2 or 3 recipient addresses. The coins stay in these recipients for more than 3 days.
I can assume that this is not a pool, because:
(1) a pool like Eligius or p2pool usually has a large number of direct payout addresses; and
(2) a pool pays out usually within a day.
I'm left with the option that this is likely to be a direct mining set-up, and that the recipients are the same person.
What do you think? Thanks!
It could easily be a small pool of friends or a club or hobbyist.
If it is a pool, then each of the addresses belongs to a different participant, and the "payout" happens immediately since the address is the participant's address. The participant may not be able to spend any of the outputs until the transaction matures after a few days.