Speaking to BBC Radio 4's Chris Vallance for iPM, Toulmin said the PCC had just commissioned research on the subject and would conduct a series of interviews to test public expectations and knowledge about uploading personal information to the web.
"We are aware that people are putting up stuff to these sites with the expectation that it is going to a limited number of people, but if they become the subject of a news story it may end up being published to a great deal more people than they initially envisaged," said Toulmin.
"That's not to say that newspapers and magazines are not entitled to take some of the information that is out there that people have volunteered, but it does mean that people should be aware that the consequences of uploading personal information online might be not quite what they had considered."
The research would assist the PCC, Toulmin added, in finding out to what extent people would change their behaviour if the knew information could be used in the media.
Complaints had been received by the PCC about newspapers using information that individuals had themselves placed on the internet, he said, adding that the extent to which individuals had attempted to make private any web-based information would be crucial to passing judgements in this area.
Grey areas still surround the extent to which newspapers can plunder social networking sites for information about people involved in news stories. No hard guidelines yet exist about the rights to privacy people can expect on these sites.
During his interview, Toulmin suggested that newspapers couldn't just take a carte blanche approach to social sites in their pursuit of information, and that an expectation of some level of privacy must be expected.
Steve Herrmann, editor of BBC News Online, last week revealed guidelines that had been issued to BBC staff when dealing with information found on social networks, stating that legal, copyright and accuracy of the image should also be at the forefront of reporters' minds when considering use of images from social sites.
Full Toulmin interview: