A survey released on Friday shows that people who have used the social networking site over a long period - since its founding in 2004, say - show no sign that they have tired of posting pictures, updating weekend plans or just relaying random thoughts.

The Pew Research Center report, based on a U.S. phone survey, logs and data from November 2010, sheds light on Facebook's possible long-term popularity as the company founded by Mark Zuckerberg heads for a $5 billion initial public offering.

Ahead of the IPO, one concern about Facebook has been that users will simply bore of it after a while, a phenomenon known as "Facebook fatigue." The Pew research suggests those worries may be unfounded.

The longer that people have used Facebook site, the more frequently they hit the "like" button, commented on friends' content, posted status updates and tagged their friends in photos, the report showed.

It also concluded that having more Facebook friends kept users more involved with the social networking site.

"The more Facebook friends users have, the more they perform every activity that we explored: friending, liking, private messages, commenting, posting, photo tagging, joining groups and poking," Pew said regarding the survey by its Internet & American Life project.

Facebook users on average can reach 156,569 other network users through friends of friends. The number is skewed by Facebook users with especially large friend lists, and the median is 31,170 people reached through friends of friends.

"This examination of people's activities in a very new realm affirms one of the oldest truths about the value of friendship," said Lee Rainie, head of Pew's Internet project. "Those who are socially active have a better shot at getting the help and emotional help they need."

The survey was based on a phone survey of 2,255 U.S. adults that was conducted in November 2010. Respondents were asked to share logs of their Facebook activity, and about 269 respondents let Facebook release data on their use.

Facebook says it has 845 million active users today.

(Reporting By Ian Simpson; Editing by Paul Thomasch)

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