Blocking software is being used by companies to prohibit access to everything from porn and hacker sites, to e-commerce:

Across the country, thousands of large and small firms — and government agencies — are installing special software that can block access to individual Web sites from employees' computers. And while many companies are only blocking the obvious suspects, such as sites featuring pornography, gambling or hate speech, some firms are taking matters a step further.

At financial powerhouse Merrill Lynch & Co., grumbling employees said they are prevented from getting to online auctioneer eBay and other e-commerce sites. Even widely used search engines are blocked for some workers.

"They tell you they trust you with a million-dollar account, or with someone's life savings, but you can't be trusted to look at the Internet," said one Merrill worker. A company spokesman acknowledged that Merrill uses the software but refused to provide further details.

....But monitoring Web use has put firms in the position of spying on their employees, which can cause friction and has mobilized privacy and workers-rights advocates. So companies are increasingly turning to a new generation of blocking software that can be highly customized.

"That's the secret to this space," said Peter Kuper, who follows the industry for investment firm SG Cowan Securities Corp. "Companies don't want to be too Big Brother-ish, but want to prevent everything from porn to malicious code." Kuper said companies are especially concerned about legal liability if their employees use the Web improperly, such as by viewing sexually explicit content that others around them can see.

In addition to preventing access to an entire class of Web sites, such as those devoted to pornography or hacking, the software can allow companies to permit other types of sites, such as entertainment or chat rooms, to be seen only after 5 p.m. or for only a certain amount of time each day. And the company can set the controls to govern use by individuals or departments.

San Diego-based Websense Inc., one of the leading vendors of what is being called employee Internet management (EIM) software, practices what it sells.

....But privacy advocates, while uncomfortable with restrictions on Internet behavior, are relieved that many companies are moving away from monitoring and toward blocking. And they recognize that workplace computers are corporate property.

"To think that Fortune 500 companies can run their Web site access completely on an honor system is a bit naive. There's too many downsides," said Lewis Maltby, president of the New Jersey-based National Workrights Institute, an employee advocacy organization.

He called monitoring of Web visits "a privacy nightmare," since people often look to the Internet for help with medical, family or financial problems. [Washington Post]