bitcoin mining is one of the best platforms regarding making money, day by day it is becoming a popular and profitable source of gaining profit. in India and China, bitcoin mining has gained huge popularity and many people are being involved in this section. bitcoin mining is the best possible stage to make double your capital within a short period of time.
Yup, totally true. The only dark side to mining is that you may risk spoiling your hardware (i.e. Overheating, or mining using laptop 
). Also,if your country's electricity bill is relatively high, your rewards from mining may not be enough to cover the bill.Thats how Bitcoin works. It rewards users (or machines) with Bitcoin for their computational power to verify transactions and to discover new blocks. The higher the price of Bitcoin, the higher the miner fees, and miners would get even more rewards, in additional to the 25 BTC per block found.
I am not so sure about how profitable mining is right now, but if you do not have a specialized BTC miner like ASICs, then do not try and mine with your regular computer and laptop, you might explode them. (the dark side)
I think the equation to measure the mining profitability today is not much more different that the modern datacenters ...
