That's not to say social networking sites haven't found success in charging members for some services.
The one major flaw with social-networking sites is that it all depends on your network.
The disruption prompted angry BlackBerry users to vent their frustrations on social networking sites like Twitter.
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Communication history, instant messaging and updates from social networking sites are all readily available.
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Facebook and other social networking sites reflect these changes but they also enhance them.
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Security experts said it makes sense that cybercriminals are turning to social networking sites.
All of which, they can send to their friends and family through social networking sites.
Tributes poured into social networking sites as friends expressed their shock at the shooting.
Consider the SEC's announcement Tuesday that it would allow companies to disclose information via social-networking sites.
Children will only be allowed to use the social networking sites if adults are present.
Other popular social-networking sites, such as Twitter and LinkedIn, don't offer a direct-sale platform.
Although social networking sites are popular, they are not yet attracting high advertising rates.
Facebook and other social networking sites were very much a victim of this skepticism.
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Internet-based social networking sites like Friendster and MySpace.com have changed the way people connect.
The lonely hearts are preyed on in chat rooms, dating sites and social networking sites.
Like the other social networking sites, it derives most of its revenues from advertising.
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Also, unlike the other social networking sites, Cancer.im allows for donations to be made.
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Like other airlines, JetBlue approached social networking sites by slowly scaling up its presence.
The gaffe was picked up by fans on social networking sites such as Twitter.
Everyone knows that evidence from social networking sites comes in handy for lawsuits and divorces.
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Manpower is acutely aware of the threat to this business posed by online social-networking sites.
To ramp up your positive Web mentions, start with blogs and social networking sites.
Asked whether Facebook and MySpace compete with dating sites, Match.com said social-networking sites have a different objective.
As social networking sites open to developers, can they keep users' private information closed to prying hackers?
Other card issuers have simply moved online, flooding students with email offers and marketing popular social-networking sites.
The Pew survey found that only 6% of Internet users in Russia were not on social-networking sites.
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Russian blogs and social networking sites celebrated the incident as a "miracle" and the pilots as "heroes".
But they're buffing up how they serve vacationers by acquiring social networking sites that focus on travel.
Karen Essman, 61, uses Facebook but said she has trouble convincing her peers to join social-networking sites.
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Those numbers suggest that the social connections on Facebook remain the strongest of the social networking sites.
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