A European Internet study has an instant message for parents who want to block their children from viewing social networking sites or blogs: few software programmes filter out such content.
A solid 84 percent of programmes restrict access to websites such as porn pages, according to a study released by the European Commission.
But only a "few tools" can block instant messaging services or filter out "Web 2.0" content such as blogs, forums and social networking sites.
And not all products on the market provide parental controls for smart phones and video game consoles.
Computers are no longer the only way to go online: 31 percent of children access the Internet with their phones and a quarter through platforms such as the Xbox or PlayStation, the study found.
A survey released in parallel to the study found that only a quarter of parents in the European Union use parental control software to monitor, track or filter online content.
The use of such software varies widely among parents in the 27-nation EU, from 54 percent in Britain to nine percent in Romania.
The EUKidsOnline survey was conducted in 25 countries with more than 25,000 children and one of their parents between April and August 2010.
The study on filtering software analysed 26 parental control tools for PCs, three for game consoles and two for mobile phones. It was funded by the EU's Safer Internet Programme.
"The study found that the existing software is good at filtering adult online content," the commission said in a statement.
"But there is still at least a 20 percent chance that sites with unsuitable material for children and especially those encouraging youngsters to self harm (sites promoting anorexia, suicide or self-mutilation) could pass through their filters," it said.