[citation][nom]amk-aka-Phantom[/nom]Rofl, nice title To all of you who b!tch about their "violated privacy"...... don't put your private data on the internets.[/citation]
Actually even if you choose not to make personal data public companies may know all about you regardless.
Let's start with an example. This very page attempts to load JavaScripts from 13 different domains. They provide tools to make page building easier but some will also help funding THG through adverts. So one could be thinking it's absolutely normal and inherent to internet. But then figure most of these scripts are used in all sort of pages so the companies who write these scripts are sure to know when you visit any of the sites as long os you run their scripts. After few weeks with browsing and thousands of pages viewed It comes to the point they have enough data to profile your browsing habits which can help boosting their advert incomes by delivering the content according to your interests. Still OK for some but others certainly dislike.
Then at last link all the data to social networking or instant massaging and you have a profile accurate enough to spot all your daily habits, relatives, career, interests... anything. All these steps occur with absolutely zero user knowledge.