The most used Instant messengers. Where do they stand these days. Which platforms. Etc.
Feel free to add your...
Features comparison table of Google Plus vs Facebook vs Twitter
Compare the differences between FaceBook Group and FaceBook Page.
Compare WhatsApp vs Facebook messenger vs Telegram vs Google Hangouts vs Skype
Compare the features of the most common image formats
Compare Location-based online services: Facebook Places vs Foursquare vs Google Latitude vs Gowalla vs Loopt
Compare GramEasy vs VTGram
Time Tracking Software - Hubstaff, Worksnaps, Time Doctor, oDesk Team
Compare Group vs Page
User reviews and comments