While both Dogecoin and Bitcoin were designed as online currencies, they are quite different. First of all, Dogecoin is inflationary while Bitcoin is deflationary, meaning that there will be an unlimited amount of Doges compared to limited Bitcoins. Also, they use different technologies behind their proof-of-work algorithms used to validate transactions. Most importantly Bitcoin is regarded as digital gold and a store of value, while Doge is just a fun meme coin.