Social network usage will rise sharply in 2010, according to a report by eMarketer.

The number of people visiting social networks on a monthly basis in the U.S. will reach 127 million, or about 57 percent of all domestic Internet users, by the end of 2010, a 16 percent increase over 2009.

By 2014, two-thirds (65.8 percent) of U.S. Internet users will be regular visitors to social networks, the firm reported.

"Marketers on social networks are on the cusp of something truly exciting: a critical mass of engaged consumers who are willing to participate, share and spread the word about the companies and brands they love," said Debra Aho Williamson, a senior analyst at eMarketer.

"But if there ever were a time to assure consumers that their information is safe and secure, and to make sure that their brand interactions on social networks are positive, that time is now," she added.