Chain btc,Block 199253,Chain Size 2000M,Cycle 2016,Next 199584,Blocks Left 331,Measured 83.58%,Current Difficulty 2694048.00000,Est Next Difficulty 2863164.44721,Est % Change 6.28%,Retarget Distance 2d 3hr 54m 29s
why's namecoin difficulty going down?
Probably because BTC Guild and Slush are running beta testing on Stratum based pools. Neither of us have currently setup merged mining in the new pool software, meaning the NMC chain lost ~450-500 GH/s this last week.
What is stratum?
It's a revised protocol for miners to communicate with pools. It changes the miner->pool relationship from pull based (miner constantly requests work) to push based (pool sends miner work at regular intervals). Part of the protocol change allows miners to generate work locally, so regardless of speed (1 MH/s -> 1 GH/s -> 1 TH/s -> 1 PH/s -> 1 EH/s > even more), the overhead in miner<->pool communication does not change. It uses less bandwidth than current protocols while being able to accommodate massive mining farms/new technology advancements over the next century.
It's currently done using a proxy that the miner runs on a machine in their network, and they point miners at the proxy, which communicates with the pool via stratum, and translates it to the old getwork protocol they're used to. Native miner support is coming this week for poclbm & guiminer, and a cgminer fork with native support might be out in another week.