"Most Web sites will not continue, only those Web sites that are part of these accepted activities would continue to operate," the senior official said. "Accepted activities," refers to essential, life and safety-related government services.

But how the government's electronic, automated operations will be affected between agencies remains to be seen. Many government Web sites included automated tools for searches and filling out forms.

Although the U.S. Small Business Administration (SBA), for instance, will be closed by a shutdown, its Web site, which includes a number of tools to help businesses, will remain operational, an agency spokesman said.

The SBA site is hosted off-site and maintained by a contractor who has already been paid, the spokesman said.

Ray Bjorklund, an analyst at Federal Sources, says static Web sites can keep running until the server crashes. But people who interact with the government via the Web have a higher risk of that interaction going unfulfilled, which might be a reason the government takes down a Web site, he said.