Will Skype stay this popular under Microsoft?

The team at Skype recently published an infographic that shows the vast usage numbers associated with its free calling services.

According to the infographic, based on daily stats gathered in July, Skype usage represents more than 255 billion minutes (or 4.25 billion hours) of calls annually, which is roughly four times more than the service saw in 2008.

Despite the tremendous growth in usage, Skype may have as many detractors as it does proponents. Its services have suffered from a number of hiccups over the last few years, including a serious bout of downtime in December 2010.

For many users (like myself) who depend on it as a work tool on a daily basis, it's long been the service we love to hate. However, adoption has continued, and it would appear that usage has grown as well.

As the company, formerly owned by eBay, moves into the corporate arms of Microsoft, frequent users wonder how Microsoft might attempt to monetize its services. It's not yet clear how Microsoft intends to make back the $8.5 billion it spent on acquiring Skype in May.

In 2009, Skype had revenue of $860 million, on which it posted an operating profit of $264 million. Overall, the company made a small loss of $7 million and had long-term debt of $686 million.

Based on some simple math, if Microsoft was justifying the $8.5 billion purchase price based on the number of people who sign in daily, they would be paying about $123 per unmonetized daily user, which is probably not too bad.

The infographic's stats don't specifically mention revenue, but Skype has implemented a number of features, including group video calling and group screen sharing for Mac users, that encourage people to pay for the service.

A quick look at the daily average stats:

• 65 million people sign into Skype daily
• 700 million minutes of Skype-to-Skype calls made daily
• 300 million minutes of video calls