Groupon has taken a step toward closer to dongle-to-dongle combat with Square with its announcement of its Groupon Merchants app for Android (v2.2), which implements Groupon Payments into the platform. In other words, Groupon’s updated Merchants app for Android devices enables merchants to accept credit card payments using Groupon Payments, which utilizes a small card reader that attaches to mobile devices. This is a shot at Square and PayPal, and a strong play by the daily-deals company at warming small businesses up to its other offerings. (MarketWatch, TechCrunch)