This is a quote from the book "On Zero Confirmation Transactions" by Chris Pacia
...of the Eligius mining pool. The pool operator believes that certain types of transactions, such as gambling transactions, constitute “spam” and should be banned from the network. So he runs a patch that checks each transaction for payments to certain addresses and refuses to include those transactions in his pool’s blocks. His code refers to it as an “is notorious” check. And this is fine, he has every right abstain from including those transactions. If he doesn’t include them, the next miner will. But the way it’s implemented is his pool doesn’t just abstain ...
read full book block explorer