Skype (News - Alert) and Viber are two of the most popular VoIP service providers on the market – so much so that many users of both are unaware of what VoIP even is, despite the fact that they use it frequently. VoIP stands for Voice over Internet Protocol, and is commonly used in conjunction with video services for instant face-to-face communications. Because this information is sent over the Internet instead of traditional phone networks, VoIP actually offers an alternative phone system that providers like Skype and Viber can offer for much lower prices.

Skype and Viber are both popular due to the fact that they offer free applications for both corporate and personal calls, and have low rates for more advanced systems with extremely powerful calling features. But which one is the better VoIP provider, and in which situations?

Skype has Viber beat on both number of available options and seniority. Skype will sync contacts across social media accounts like Facebook (News - Alert) as well as email addresses, and is available as a mobile, tablet and desktop platform. Skype's audio and visual quality is also far higher than Viber's, although the mobile platform has slightly more steps than Viber does.

Viber may be a much younger company, but its ease of use as well as the ability to make free international calls has catapulted the company into the limelight. It was designed as a mobile platform first while Skype was birthed on the desktop, which makes it much friendlier for smartphones.

Ultimately, both platforms are excellent choices for free VoIP services, so choosing either is largely based on the customer's individual preferences. If the company expects international calls and a high mobile presence, Viber may be the best option, although Skype may be better suited to desktop-focused business environments.