According to Reuters, Saudi regulators blocked the service because it was too difficult to monitor and because it sucked revenue from telecom outfits. The fact that Viber was created by an Israeli probably didn’t help much, either.
Earlier this year the Saudi Ministry of Interior complained that Islamist militants were taking advantage of social media to encourage unrest, but it did not recommend imposing stricter controls. In the end it might have a bit more to do with the three Saudi telecoms wanting to squash competition than militants or personal freedoms.
But it is a good example of how tech is bringing the world together – Islamist militants using an Israeli app to bring down the Wahabi House of Saud, what more could you ask for? [An atheist angle. Ed]