Ontario's privacy commissioner says people's perceptions of their privacy and anonymity online fall far short of reality.
Dr. Ann Cavoukian says seemingly unrelated pieces of information that people share about themselves online may now be linked together to create a detailed profile.
Ms. Cavoukian says new analytic tools and algorithms now make it possible to combine information from multiple sources.
This allows the creation of an accurate profile of a person and their online activities.
She warns people to consider the nature of the information they share, and how their personal information might be used.
Ms. Cavoukian is also urging organizations that collect and use this data to offer a clear, easy-to-use mechanism to opt out of the collection and use of personal information.
"We have reached a point where information — not only strongly identifiable Social Insurance Numbers, but also IP addresses, licence plate numbers and mobile devices — serve as pointers to personally identifiable information," Ms. Cavoukian said.
"This bears little resemblance to anonymous information," she added.
"Imagine a scenario where your 'anonymous' comments on a newspaper website or in an online chat forum, could be tracked back to you personally, simply by linking your IP address and browser data across multiple platforms," she said.