yes i have seen those before but for every one of these low fee spams there are so much more with higher fees.
and bitfury only finds 11% of the blocks nothing more. so that would be practically ineffective because other miners reject them.
But for every one of these low fee tx's (sending nothing exept a fee) included in a Bitfury block, another higher paying fee is not included, meaning fees rise further. 140,000 tx's from 1 addy, sending nothing except low fee, have been included in Bitfury blocks, while "recommended fee" paying tx's (6x higher fee or more) are left in the mempool.
140,000 tx's at 386 bytes equals around 5.5 blocks created by 1 addy, mined by Bitfury, sending 0 btc.
Can't be helping anything.
Ctrl+F the address it contains 252 of these transactions and it seems like bitfury is not the only miner picking these up after all!
p.s. the block was mined during the spam attack while mempool was full (2017-04-15 11:09:19)