Mining bitcoins is a lot like fishing. It starts out with hearing stories of people catching lots of fish and and selling them for lots of money and then you think you should do it too.
Try to imagine a small lake with about 21,000,000 fish. The first people to fish it were getting lots of fish but the fish weren't worth a lot of money yet either. Suddenly, the value of the fish goes up and now more people show up to fish. However, to keep too many fish from being caught too quickly, the size of the lake adjusts every two weeks. Since the lake keeps getting bigger and bigger, the fishermen start using better tackle and more poles. Eventually, they buy boats and trawlers, nets, etc. The lake is now an ocean. Soon, fishermen put their resources together to catch more fish and split the profits. All the while, the ocean keeps expanding, making fishing difficult for anyone who doesn't have the means to buy fancy boats, etc.
Enter your plans to mine:
You decide to get in on the fishing because the fish keep going up in value. Online you find a tiny boat and pole and buy them. Well, the local fishermen are fine with you joining their pool of resources but you quickly find out that your split of the fish isn't that much because you are only a small boat and pole, while they are bringing up large nets full of fish. If only you had the equipment they did. Then you come to the realization that your boat has been consuming gas this whole time. Well, you sell some of the fish you got but it isn't enough for gas...
That is bitcoin mining in a nutshell. If you can't afford the fancy trawlers, don't expect to catch much fish now.
Why not just buy some of the fish now and wait for the price to go up?
Very true.
But the problem is that people don't really understand difficulty adjustments and how it affect the mining revenue.
