Bitcoin has a polar opposite in the digital currency world: Zen.
One of the most popular Bitcoin alternatives by trading volume has been Litecoin.
A service to track profits earned for virtual currencies provides what you might call a "Google Finance" for alternative currency portfolios.
Robocoin Kiosk, a machine that lets people buy and sell bitcoins, will be demonstrated at the #Bitcoin2013 conference this weekend.
Google Ventures and China-based IDG Capital Partners place a bet on OpenCoin, the company behind Bitcoin exchange Ripple.
Amazon has handed 500 "Amazon Coins" to each of its US-based Kindle Fire customers.
Bitcoin isn't the only form of electronic money being mined, traded and spent these days.
A CoinDesk Q&A with Stan Stalnaker, founder of Hub Culture and the Ven digital currency.
Amazon is set to launch its own in-house currency -- Amazon Coin -- this month.
Bitcoin's long-term chances of success are better if there are many other alternative, digital currencies, with many businesses investing in them.