WhatsApp Inc. is an early stage technology startup founded in the heart of Silicon Valley. What does the name mean you ask? Well, WhatsApp is a pun on What's Up in case you didn't get it yet:)
Why? -- We want to build a better SMS alternative. Because we believe we can. Because someday very soon everybody will have a Smartphone.
Who? -- WhatsApp was founded by two guys who spent combined 20 years doing geeky stuff at Yahoo! Inc. before starting WhatsApp Inc.
By Operating System