Short answers, pulled from the story.
Colin LeMahieu created Nano and launched it in October 2015. He began developing the project in 2014 under the original name RaiBlocks, intending to address the Bitcoin scalability problem by eliminating transaction fees and reducing confirmation times to under one second.
Nano uses a directed acyclic graph structure implemented as a block-lattice, where every account maintains its own independent blockchain. Each block records a single transaction and the account's current balance at that moment. Nano is the first cryptocurrency to implement this structure.
When two contradictory transactions from the same account reach the network simultaneously, Nano's nodes vote on both. The first transaction to accumulate 67% of the total voting weight is confirmed as valid, and the other is rejected.
Nano, then called RaiBlocks, was distributed for free through a captcha-secured internet faucet. The faucet ran until 126,248,289 units had been claimed and closed in 2017. A developer fund of 7,000,000 units was added, bringing the total fixed supply to 133,248,297.
On the 9th of February 2018, the Italian exchange BitGrail announced it had been hacked and was shutting down, leaving users unable to access assets worth 17 million Nano. In January 2019, a court in Florence found BitGrail guilty of failing to implement safeguards and failing to report its losses. Italy's Network Operations Command separately alleged that the exchange's owner, Francesco Firano, had committed fraud.
Each Nano account holds voting weight proportional to the amount of Nano it holds. Holders delegate this weight to a representative node of their choice, and those nodes cast votes on transactions. A transaction is confirmed once it accumulates 67% of the total voting weight across the network.