The majority of existing cryptocurrencies, including Bitcoin and Ethereum, have transparent blockchains. Transactions can be verified and/or traced by anyone in the world. This means that the sending and receiving addresses of these transactions could potentially be linked to real-world identities.
Monero, on the other hand, uses various privacy-enhancing technologies to ensure the anonymity of its users.
Unlike selectively transparent alternatives (e.g. Zcash), Monero is the only major cryptocurrency where every user is anonymous by default. The sender, receiver, and amount of every single transaction are hidden through the use of three important technologies: Stealth Addresses, Ring Signatures, and RingCT.
Because every transaction is private, Monero cannot be traced. This makes it a true, fungible currency. Merchants and individuals accepting Monero do not need to worry about blacklisted or tainted coins.
With Monero, there are no wire transfer or check clearing fees, no multi-day holding periods, and no fraudulent chargebacks. Because Monero is decentralized, it is not constrained by any particular legal jurisdiction and provides safety from capital control.
The Monero Project is at the forefront of cryptocurrency privacy and security. Its Research Lab and Development Team are constantly working on new, innovative technologies. Since its launch, the project has received contributions from over 500 developers located all around the world.
Numerous forums and chat channels are available for anyone to join, and the community is always welcoming new members.