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Question: When a block is found on the network, obliviously the pool that mined it is the first to know and first to mine a new block!. How long does it take for the other pool to be notified ? and is this a real factor
That depends on how well connected the pool is.
The problem is actually if they are not well connected, they will get more orphans.
So the smaller the time until every other pool knows about your block, the better.
It is not to your advantage to hide or delay the fact you found a block ...
Having 'extra' time to mine a block is not an advantage.
That 'extra' time is very small ('should' be less than 1 second) but it's not 'extra' time as such, it's actually time for some other pool to get into an orphan race with you by finding a block at the same height, which is, of course, bad.
Thanks Kano. Very interesting. So seeing pool pulling many block In-A-Row is just luck I guess.