As more and more ASIC are being shipped by Butterfly Labs, more and more GPU miners falling off the network due to they’re not making any money and possibly loosing money due to electric bill. It is all caused by the level of difficulty of bitcoin BTC risen dramatically and will probably rise 100 times higher in short period of time compare to previous calculation. So even if you can mine at 1tera hash/s you’re making barely making enough money to pay for electric bill. On top of that the BTC price had crashed again to below $90 per unit.
That’s right BTC price had gone down to below $90 following several days after big announcement from Butterfly Lab that they will start massively ship ASIC miner which can mine hundreds of time faster than GPU could, so say good bye to your GPU, sell it on ebay, or mine Litecoin.