A new reason to stay off the Web at work..

When Proctor & Gamble shut down some access to the Internet this week, it wasn't to keep employees from messing around on Facebook or crafting personal e-mails on company time.

Instead, it was to get them to quick sucking up the company's Web bandwidth by listening to music and watching movies.

In a memo Tuesday, the company, which sells everything from Tide detergent to Pringles to Duracell batteries, told its 129,000 employees they can no longer use music-streaming site Pandora or movie site Netflix at work.

"We are one of the more lenient companies in terms of providing access to the internet, but there are some sites which don't serve a specific business purpose -- in this case, Netflix and Pandora," Proctor & Gamble spokesman Paul Fox said in an e-mail. "They are both great sites, but if you want to download movies or music, do it on your own time."

According to the memo, an internal report found that P&G employees were watching 50,000 five-minute YouTube videos and listening to 4,000 hours of music on Pandora on a typical day. At one point, the company's Web capacity was overtaxed, "requiring immediate interaction," the memo said.

Since the company uses YouTube as a tool to sell its products, Netflix was banned instead in the effort to free up bandwidth.

Since the dawn of the Internet age, companies have struggled with how to handle personal computer use while employees are on the clock. It's not rare for companies, both large and small, to ban some or all personal Internet and even e-mail use.

But, as more and more businesses need Web access to function (and as web content becomes more data-intensive) many are struggling with a so-called bandwidth "spectrum crunch."

Wireless carriers are also struggling with the issue. The growth of the smartphone and tablet markets have dramatically increased the amount of data being accessed at any given time. Global mobile data traffic is just about doubling every year and will continue to do so through at least 2016, according to Cisco's Mobile Visual Networking Index, the industry's most comprehensive annual study.

Steve Feller, a steering committee member of an IT professional group in Cincinnati (where Proctor & Gamble is based) told the Cincinnati Enquirer that social networking and other personal computer use has become a serious concern at some companies, threatening to slow the flow of data.

"Effective IT leaders need to address this within their companies now," said Feller. "It is not something to be ignored."

But it's not just employees. Companies themselves are using the web more. The rise of cloud computing means that a lot of data that once would have been stored internally is being accessed from the web, sometimes multiple times in a day.

"As P&G drives to become one of the most digitally advanced companies in the world, more and more of our business processes, applications and systems are being web enabled," Fox said in the e-mail. "That in turn makes bandwidth capacity and availability even more critical."

Ad Age notes that Netflix and Pandora competitors -- such as Spotify, Hulu and Vudu -- aren't blocked, although the company says Tuesday's move may just be a first step.