The earliest notable altcoin, Namecoin, was based on the Bitcoin code and used the same proof-of-work algorithm - and like Bitcoin, Namecoin is limited to 21 million coins. Introduced in April 2011, Namecoin primarily diverged from Bitcoin by making user domains less visible, allowing users to register and mine using their own .bit domains, which was intended to increase anonymity and censorship resistance. 
Bitcoin is pseudonymous rather than anonymous in that the cryptocurrency within a wallet is not tied to people, but rather to one or more specific keys (or "addresses").[41] Thereby, bitcoin owners are not identifiable, but all transactions are publicly available in the blockchain.[41] Still, cryptocurrency exchanges are often required by law to collect the personal information of their users.[41]
Around 2008, Satoshi Nakamoto founded Bitcoin. At the time, a paper was published through the Cryptography Mailing List. The first Bitcoin software client was released in 2009, and he collaborated with many other developers on the open-source team, careful never to reveal his identity. By 2011, the enigmatic Bitcoin founder had disappeared. His peers understood how valuable this cryptocurrency was, and worked feverishly to develop it to its maximum potential.