In the past 24 hours there have been 14 empty blocks:
BW.com - 3 of their 7 blocks were empty
AntPool - 7 of their 44 blocks were empty
f2pool - 4 of their 31 blocks were empty
Does this mean that they are working on blocks without transactions?
How is this possible?
I'm guessing that this makes it easier for them to mine with these blocks, therefore, higher chance of finding the payoff block?