https://www.reuters.com/article/us-crypto-currency-ethereum-dogecoin/elon-musk-back-on-twitter-turns-his-attention-to-dogecoin-idUSKBN2A417H >Cryptocurrency Dogecoin surged more than 60% on Thursday after billionaire entrepreneur Elon Musk tweeted about it, two days after he said he was to take a break from Twitter "for a while".