Facebook, MySpace and Google signed a pact with the European Union on Tuesday to improve safeguards against the bullying and abuse of teenagers online.
The EU said networking sites are currently used by some 42 million people in the bloc and warned that youngsters need to be protected from abusive behavior.
The agreement signed by 17 site operators in the EU commits them to limit the risks of misuse by providing a "report abuse" button. This allows users to report "inappropriate contact from or conduct by" another user to the site operator, which will relay the complaint to local authorities.
The site operators also must make sure online profiles and contact lists of underage users are set to the highest privacy settings and to ensure they are not obtainable on search engines.
EU officials said the pact is voluntary, but aim to push the same minimum safeguards on network sites used across Europe. The EU also released a video clip to raise awareness among parents and teenagers on Internet use.
Experts have urged parents to discuss Internet use with their children to make sure they are aware of the possible dangers if they post personal details online.
"Social networking has enormous potential to flourish ... as long as children and teenagers have the trust and the right tools to remain safe when making new friends and sharing personal details online," said EU Media Commissioner Viviane Reding.
She said that as more teenagers go online, they face a growing risk of abuse, including cyberbullying or grooming by adults who intend to commit sexual abuse.
She pointed to EU-wide research which found that cyberbullying was on the rise.
A July 2008 survey found that 52 percent of Polish Internet users aged between 12 and 17 were exposed to abuse on the Internet or when they used mobile phones.
The popularity of social networking sites rose by 35 percent in the EU in 2008. The Commission said it expects the number of users to rise to 107 million in the next four years.
Similar agreements already have been signed between networking sites and authorities in the United States.
MySpace and U.S. authorities announced earlier this month it had identified and removed some 90,000 sex offenders from its networking site.
Facebook and MySpace already have implemented dozens of safeguards, including finding better ways to verify user's ages, banning convicted sex offenders from using the sites and limiting the ability of older users to search members under 18.
A further update in user policy was announced by Facebook last week, offering more privacy and security to under 18-year-olds.
Luc Delany from Google also said his company was redoubling efforts to protect minors using its sites.