When Google Inc.'s online-email service shut off for over two hours last week, it brought to light concerns about whether businesses can safely rely on software that their employees access over the Internet.

Online software services like Google's Gmail — which run on vast computer farms managed by companies like Google and Salesforce.com Inc., rather than businesses installing and operating the software themselves — are a bright spot for the technology sector: Sales grew 27 percent in 2008 to $6.4 billion, according to research company Gartner.

Such services are also often cheaper to operate and easier to get started on, making them attractive options during a recession.

Google's Gmail is one of the most widely-used pieces of online software. Most users are familiar with the free version.

Google also sells a suite of online-software services, including an advanced version of Gmail, to companies for $50 a year per user account.

But companies are finding that going online to do business-computing tasks via services like Google's or similar ones offered by Amazon.com Inc. and Salesforce.com, among others, comes with a risk: When something goes wrong, customers must sit idly while waiting for someone else to fix the problem.

"Any time there is a failure it creates concern," said John Dohm, vice president of information technology at True Religion Apparel Inc.

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