An experimental app lets you shoot money over to your friends through Twitter messages. It's not perfect, but something Twitter could use to make a buck or two.
MapReduce and Hadoop power some of the most data-intensive applications. This video presentation explains how they work.
We checked out the mobile payment app Square, which can track cash payments in addition to letting you swipe credit cards from your Android phone.
eBay is trying to keep developers from straying to the Amazon fold with a new payments interface with more flexibility for new types of online purchases.