This operation currently mines about $262k per month:
230e9 (each machine does 230 Ghash/s) * 2500 (# of machines) * 3600 (second/hour) * 730 (hour/month) / (2^32 (average number of hashes to solve a block at diff=1) * 19.8e9 (current Bitcoin difficulty)) * 25 (BTC/block) * 590 (USD/BTC) = $262000/month
The article says their electricity bill is $60k per month. Subtract the 3 employees salaries, say $5k per month (this is China). So you are looking at a pure profit of $197k per month. Of course these profits are declining quickly over time; look how fast the difficulty has been rising: http://bitcoin.sipa.be/speed.png (logarithmic scale!)
And this mine only represents 0.3% of the total network speed (about 170,000,000 Ghash/s).
Edit: bellerocky: most exchange fees are < 1% to turn BTC to fiat.
Edit: FigBug: roughly yes, but because the network is growing, there are more than 3600 coins mined per day (blocks are solved a bit more often than every 10min).
The article says their electricity bill is $60k per month. Subtract the 3 employees salaries, say $5k per month (this is China). So you are looking at a pure profit of $197k per month.
Three other significant expenses worth considering: rent/physical plant, hardware, and taxes.
In most cases in mainland China, no tax is paid and cash is king. Only if you are a large, visible company doing business with other large, visible companies do you need to get formalistic. Even then, double or triple sets of accounts are normal.
I pay plenty of taxes. Heck, I pay the tax on my rent for a fapiao that gives me a tax benefit at work. The PRC is getting better about tax collection, though a lot of activity still goes on underground, especially those that are related to money laundering.
It's $200k/month worth of Bitcoin. The 'liquidity' we're talking about here is converting Bitcoin into local currency that you can purchase things with.
I think for this kind of work $5k is already too much for three Chinese workers. Each worker about $500 and maybe some fees for the living room and food. If you pay $2k it might be fine.
If you pay $5k for such kind of 24/7 job in China you'll make a middle man very happy.
Using this calculator https://alloscomp.com/bitcoin/calculator and using 575,000 Gh/s (is that right?) the calculator gets about $260k per month. With $60K for electricity and let's say $10k for misc. overhead I would guess they are clearing close to $190k per month.
