I don't know how the matters stand at the moment, but in August there was a transactional glut, i.e. there were a few thousand unconfirmed transactions that didn't get confirmed in time (up to 50,000, if I'm not mistaken). I got caught too, my ~1 BTC transaction hadn't been confirmed for 2 days. I guess it was a deliberate effort by miners to stimulate the price, since I saw a lot of new blocks with only the miner's TX in them...
Therefore, it is hard to predict what the miners can be up to
That was because the stresstests. Someone created piles of junktransactions with a sligthly higher fee than legit transactions so that miners included the more expensive transactions and normal transactions got stuck. The problem was not that too view miners exist but that each block only can hold transactions worth 1mb of data
This is what I had been told. But it's cold comfort, given that I got caught personally (for 2 days, Carl!) and generally don't believe such stories, lol. The theory of the more expensive transactions crowding out normal transactions doesn't hold since it fails to provide a viable explanation for empty blocks...
Um, that is no theory. We know who did the stresstest, we know the transactions that were spam and so on. The empty blocks have a different explaination and they happen all the time. Regardless of spam attacks.
The reason for empty blocks are that some miners think they will have an advantage when they create a very tiny block. Because you will win the 25Bitcoins when >50% of all nodes accept your block as the next valid block. So if you send out a very small block then chances are that your block will be spread very fast through the bitcoin network. Maybe you even will orphan a big block that was created a second before your block.
Though that is not a really usefull way to handle things. Because someone created a propagation network. He can propgate full blocks in a matter of a couple seconds. Which means it is very fast. Even with full blocks. No need to use empty blocks then anymore when you use that network.
But empty blocks and spam attacks have nothing to do together.