Privacy coins can seem shady or mysterious. Privacy coins can be owned by anyone, in any amount and sent to anyone at any time without anyone knowing. Privacy coins are essentially the digital equivalent of cash. Below is a brief description of some of the most popular privacy coins.
Monero was launched in April 2014. It was a fair, pre-announced launch of the CryptoNote reference code. There was no premine or instamine, and no portion of the block reward goes to development. See the original Bitcointalk thread here. The founder, thankful_for_today, proposed some controversial changes that the community disagreed with. A fallout ensued, and the Monero Core Team forked the project with the community following this new Core Team. This Core Team has provided oversight since.
Monero has made several large improvements since launch. The blockchain was migrated to a different database structure to provide greater efficiency and flexibility, minimum ring signature sizes were set so that all transactions were private by mandate, and RingCT was implemented to hide the transaction amounts. Nearly all improvements have provided improvements to security or privacy, or they have facilitated use. Monero continues to develop with goals of privacy and security first, ease of use and efficiency second.
Users must be able to trust Monero with their transactions, without risk of error or attack. Monero gives the full block reward to the miners, who are the most critical members of the network who provide this security. Transactions are cryptographically secure using the latest and most resilient encryption tools available.
Monero takes privacy seriously. Monero needs to be able to protect users in a court of law and, in extreme cases, from the death penalty. This level of privacy must be completely accessible to all users, whether they are technologically competent or have no idea how Monero works. A user needs to confidently trust Monero in a way that this person does not feel pressured into changing their spending habits for risk of others finding out.