An unknown number of people were cut off from Google Inc.'s search engine, e-mail and other online services Thursday, sparking a flurry of frustrated venting that served as a reminder of society's growing dependence on Google's technology.

Without providing specifics, Google said technical problems had prevented a "small subset of users" from getting into their e-mail accounts. The e-mail issues also had a ripple effect on other services, including the Google's search engine, according to the Mountain View-based company.

The intermittent trouble lasted for hours before the issues were fixed by early afternoon EDT

Before the repair, many people locked out from Google went elsewhere on the Internet to express their dismay and despair.

Multiple messages posted on Twitter, a popular information-sharing forum, indicated that people all over the world had trouble with the Google search engine and e-mail. But other Twitter users said their Google services have been running smoothly.

Because Google is used by hundreds of millions of people, even a breakdown affecting a small percentage of its audience can have a major impact. Google's search engine, by far the most popular on the Internet, fields more than 9 billion monthly search requests in the United States alone.

As part of its effort to retain its current users and expand its market share so it can sell more Internet ads, Google has invested billions of dollars to create a vast network of computers to lessen the chances of breakdowns.

Although its search engine is renowned for its reliability, Google isn't fail-safe. Its 5-year-old e-mail service, in particular, has been susceptible to periodic outages.