If you thought Facebook was completely private, think again.

The social media giant acknowledges that it has been able to create a running log of web pages that each of its 800 million users visited over the last three months.

Facebook relies on tracking cookies -- similar to systems used by Google and Yahoo. Businesses seek the info to tailor ads to specific consumers.

Craig Spiezle, executive director of the nonprofit Online Trust Alliance says it makes public too much of someone's personal information. "Its not just the tracking, but who is it being shared with, how is it being used and how do you opt of it?"

He says to protect yourself, Facebook users need to be aware of what they post online. "Once you post it, you have to assume that information is being seen and shared by millions of people, so you have to use discretion whether its yourself, your children, or your friends and family."

Spiezle recommends using the most up-to-date browsers like Firefox and Internet Explorer 9 that have privacy settings already built in, "And then limit the amount of data, be conscious about who you are sharing data with."

New guidelines for online privacy are being debated in Congress and by the World Wide Web Consortium, which sets standards for the internet.

"We have become what I called a short-burst society, and we've become so fixated by having to let people know online what we're doing and where we are and we have to think about how that data can be used in the wrong hands" said Spiezle.