Computing power is often bundled together or "pooled" to reduce variance in miner income. Individual mining rigs often have to wait for long periods to confirm a block of transactions and receive payment. In a pool, all participating miners get paid every time a participating server solves a block. This payment depends on the amount of work an individual miner contributed to help find that block.
After a certain amount of transactions have been verified by a miner, they will receive newly minted bitcoins for their work and thus new bitcoins will be added into circulation, while the number of bitcoins in circulations are now in the multi-millions range, the maximum amount of bitcoins that can ever be created is capped at 21 million. The creation rate is automatically halved every few years as more bitcoins are added into circulation, whilst this system is modeled after gold, mining difficulty is always increasing and makes finding new bitcoins more rare as the number of available bitcoins reaches the 21 million cap.
The use of bitcoin by criminals has attracted the attention of financial regulators, legislative bodies, law enforcement, and the media. In the United States, the FBI prepared an intelligence assessment, the SEC issued a pointed warning about investment schemes using virtual currencies, and the U.S. Senate held a hearing on virtual currencies in November 2013. The U.S. government claimed that bitcoin was used to facilitate payments related to Russian interference in the 2016 United States elections.