I'm the author of the post. I didn't include a lot of background detail because I wanted to publish the technically interesting bits quickly. As I see it, mining LiteCoins on EC2 is currently profitable because of four main factors:<p>1) Bitcoin's recent dramatic increase in value. (LiteCoin's value is heavily correlated to Bitcoin's.)<p>2) The relatively low difficulty level for LiteCoin mining right now.<p>3) Spot instance pricing for the EC2 GPU (g2.2xlarge) instances.<p>4) LiteCoin can be mined using both GPUs and CPUs (although GPUs are dramatically better, another ~35 khashes/sec from the CPUs is still nice).<p>Interestingly, the previous average historical spot price for these instances was ~$0.075/hour. The spot pricing has now jumped to $0.10-$0.12, depending on region.<p>As an added bonus, you may be able to get $100 of AWS credit at <a href="http://aws.amazon.com/big-data/powerof60/" rel="nofollow">http://aws.amazon.com/big-data/powerof60/</a> which would give you 2-3 free days of mining.