With the largest variety of markets and the biggest value - having reached a peak of 18 billion USD - Bitcoin is here to stay. As with any new invention, there can be improvements or flaws in the initial model however the community and a team of dedicated developers are pushing to overcome any obstacle they come across. It is also the most traded cryptocurrency and one of the main entry points for all the other cryptocurrencies. The price is as unstable as always and it can go up or down by 10%-20% in a single day.
On 24 August 2017 (at block 481,824), Segregated Witness (SegWit) went live. Transactions contain some data which is only used to verify the transaction, and does not otherwise effect the movement of coins. SegWit introduced a new transaction format that moved this data into a new field in a backwards-compatible way. The segregated data, the so-called witness, is not sent to non-SegWit nodes and therefore does not form part of the blockchain as seen by legacy nodes. This lowers the size of the average transaction in such nodes' view, thereby increasing the block size without incurring the hard fork implied by other proposals for block size increases. Thus, per computer scientist Jochen Hoenicke, the actual block capacity depends on the ratio of SegWit transactions in the block, and on the ratio of signature data. Based on his estimate, if the ratio of SegWit transactions is 50%, the block capacity may be 1.25 megabytes. According to Hoenicke, if native SegWit addresses from Bitcoin Core version 0.16.0 are used, and SegWit adoption reaches 90% to 95%, a block size of up to 1.8 megabytes is possible.[citation needed]
Miehe still runs his original mine, a half-megawatt operation not far from the carwash. But his main job these days is managing hosting sites for other miners and connecting outsiders with insiders—and he’s OK with that. He sold off some of his bitcoin stack, just after Christmas. He’s still bullish on crypto, and on the basin’s long-term prospects. But he no longer has any appetite for the race for scale. Gone are the glory days when commercial miners could self-finance with their own stacks. Today, you need outside financing—debt—which, for Miehe, who now has two young children, would mean an unacceptable level of stress. “I’ve already done it,” he says. “My entire data center was built with bitcoin, from nothing. I’ve already won enough for what I was looking for out of mining.” He pauses. “The risk and reward is getting pretty great,” he says. “And I’m not sure I want to be on the front line of that battle.”

As more miners join, the rate of block creation will go up. As the rate of block generation goes up, the difficulty rises to compensate which will push the rate of block creation back down. Any blocks released by malicious miners that do not meet the required difficulty target will simply be rejected by everyone on the network and thus will be worthless.
How hard are the puzzles involved in mining? Well, that depends on how much effort is being put into mining across the network. The difficulty of the mining can be adjusted, and is adjusted by the protocol every 2016 blocks, or roughly every 2 weeks. The difficulty adjusts itself with the aim of keeping the rate of block discovery constant. Thus if more computational power is employed in mining, then the difficulty will adjust upwards to make mining harder.  And if computational power is taken off of the network, the opposite happens. The difficulty adjusts downward to make mining easier.

You can look at this hash as a really long number. (It's a hexadecimal number, meaning the letters A-F are the digits 10-15.) To ensure that blocks are found roughly every ten minutes, there is what's called a difficulty target. To create a valid block your miner has to find a hash that is below the difficulty target. So if for example the difficulty target is
That’s all transactions are—people signing bitcoins (or fractions of bitcoins) over to each other. The ledger tracks the coins, but it does not track people, at least not explicitly. Assuming Bob creates a new address and key for each transaction, the ledger won’t be able to reveal who he is, or which addresses are his, or how many bitcoins he has in all. It’s just a record of money moving between anonymous hands.
The receiver of the first bitcoin transaction was cypherpunk Hal Finney, who created the first reusable proof-of-work system (RPOW) in 2004.[21] Finney downloaded the bitcoin software on its release date, and on 12 January 2009 received ten bitcoins from Nakamoto.[22][23] Other early cypherpunk supporters were creators of bitcoin predecessors: Wei Dai, creator of b-money, and Nick Szabo, creator of bit gold.[24] In 2010, the first known commercial transaction using bitcoin occurred when programmer Laszlo Hanyecz bought two Papa John's pizzas for 10,000 bitcoin.[25]
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