Google News, Google's popular news aggregation service, was unavailable for a significant number of users for about two hours on Tuesday.

"Today, from about 12:25 p.m. to 2:20 p.m. PDT, many users experienced difficulties accessing Google News," a Google spokesperson said in an e-mailed statement. "We know how important Google News is to our users, and we take issues like this very seriously. This issue has now been resolved. We apologize for the inconvenience."

Google's spokesperson declined to provide further technical detail about the cause of the outage.

Web site service problems are fairly common. Some Facebook users, for example, had trouble logging into the site on Monday. Those issues have since been resolved.

On May 14, Google's Gmail service was inaccessible for many users for about an hour. A limited number of users were affected by a 20 minute outage on May 8. A more significant Gmail outage occurred in February.

Google maintains an Apps Status Dashboard to provide performance information about its Google Apps services, for which the company charges some users. But the company does not offer information of this sort about many of its free services, despite their popularity.

In early September, Gmail, which is part of Google Apps, was down for about 90 minutes for most users.

An incident report that Google published following the outage explains that the problem was due to a router overload that occurred after some routers were taken offline for maintenance.

Users of Google Apps Premier Edition are guaranteed 99.9% availability through Google's Service Level Agreement.

Though Google News offers no such promise, users always have the option to visit an alternate news aggregation site in response to a service interruption.

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