Dogecoin is a cryptocurrency featuring a Shiba Inu from the "Doge" Internet meme on its logo. It was introduced on December 8, 2013. Compared to other cryptocurrencies, Dogecoin has a fast initial coin production schedule: there will be approximately 100 billion coins in circulation by the end of 2014 with an additional 5.2 billion coins every year thereafter. As of 10 October 2014, over 94 billion Dogecoins have been mined. While there are few mainstream commercial applications, the currency has gained traction as an Internet tipping system, in which social media users grant Dogecoin tips to other users for providing interesting or noteworthy content.
Dogecoin was created by programmer Billy Markus from Portland, Oregon, who hoped to create a fun cryptocurrency that could reach a broader demographic than Bitcoin. In addition, he wanted to distance it from the controversial history behind Bitcoin, mainly its association with the Silk Road online drug marketplace. At the same time, Jackson Palmer, a member of Adobe Systems' marketing department in Sydney, Australia, was encouraged on Twitter by a student at Front Range Community College to make the idea a reality.
After receiving several mentions on Twitter, Palmer purchased the domain dogecoin.com and added a splash screen, which featured the coin's logo and scattered Comic Sans text. Markus saw the site linked in an IRC chat room, and started efforts to create the currency after reaching out to Palmer. Markus based Dogecoin on the existing cryptocurrency, Luckycoin, which features a randomized reward that is received for mining a block, although this behavior was later changed to a static block reward in March 2014. In turn, Luckycoin is based on Litecoin, which also uses scrypt technology in its proof-of-work algorithm. The use of scrypt means that miners cannot use SHA-256 Bitcoin mining equipment, and that dedicated FPGA and ASIC devices used for mining are complicated to create. Dogecoin was officially launched on December 8, 2013. The Dogecoin network was originally intended to produce 100 billion Dogecoins, but later, it was announced that the Dogecoin network would produce infinite Dogecoins.
If you want to know more then check out the full Dogecoin Wikipedia article