Facebook (NASDAQ:FB) recently announced a deal valued at $19 billion to acquire WhatsApp -- a multi-platform messaging service. Nineteen billion dollars is a big sum to pay for any company, but especially for one that already has a potentially formidable competitor.

Last week, WhatsApp experienced the longest outage in its history. During the four hours the service was down, users scrambled to download a new messaging app. The event triggered nearly 5 million downloads of an app called Telegram in the short period WhatsApp was down. Further, the app shot up to the top free download in Apple's App Store charts in 46 countries.

With an app that basically looks like a clone of WhatsApp so capable of serving as an alternative to Facebook's new subsidiary, did Facebook overpay?

In the following video, Fool contributor Daniel Sparks takes a closer look at WhatsApp's rising competition.