Billy Markus is a software engineer best known as one of the co-founders of Dogecoin, a cryptocurrency that started as a joke based on the popular Doge meme. He created Dogecoin in 2013 alongside Jackson Palmer to provide a fun and accessible alternative to more serious cryptocurrencies like Bitcoin. Markus has since distanced himself from the project but remains a prominent figure in the cryptocurrency community. He often shares insights on social media and engages with fans, emphasizing the importance of community and humor in the world of digital currencies.