The Internet may be booming with new modes of entertainment and collaboration, but most companies are no longer letting their employees enjoy them during work hours.

According to new data collected by ScanSafe, which filters more than a billion Web queries each month, some 76 percent of companies are now blocking social networking sites -- a 20 percent increase over the past six months.

More companies now block social networking sites than block Webmail (58 percent), online shopping (52 percent), or sports sites (51 percent), ScanSafe says.

"Social networking sites can expose businesses to malware, and if not used for business purposes, can be a drain on productivity and bandwidth," says Spencer Parker, director of product management at ScanSafe. "Given the option, companies are increasingly taking a sterner approach to the sites that their employees are allowed to access. I imagine before long, social networking will be up there with pornography in terms of categories blocked."

Companies are also increasing their restrictions on other types of sites, including travel, restaurants, and job hunting sites, according to the data.

"When Web filtering first became an option for companies, we generally saw them block access to typical categories such as pornography, illegal activities, and hate and discrimination," comments Spencer Parker, director of product management at ScanSafe. "In recent months, employers are obviously wising up to the dangers and negative impact on productivity linked to certain sites, and more and more of our customers have chosen to block social networking, online banking, and Webmail."

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