The date of launch is the day a cryptocurrency, token or blockchain network first became live, and data sites list it to show how old a project is. For a new blockchain it usually means the day its genesis block was created or its mainnet opened to the public; for a token it may mean the token generation event, the end of a sale or the first day it could be traded on an exchange. Because these events can be weeks or months apart, different sources often give different launch dates for the same asset. The date matters to readers because a long track record says something about survival, while a very recent launch means little price history and a higher risk of failure. Also see testnet.