It might not seem dangerous for a person to leave some pieces of personal information on the Internet since everyone tends to do this. But the truth is that if someone ever tries to collect those pieces of information together, he might be able to find out the true identity of the person in reality after analyzing the collected data, which is what we call “cyber hunting”. This work focuses on the question of “what kind(s) of personal information will lead to a higher risk of personal re-identification on the Internet?” To answer this question, we conducted a case study of PTT-and-FB linkage and share effective suggestions for Internet users to avoid being cyber hunted. At the end of this work, we found that the three attributes of gender, birthday and location are more sensitive compared to other attributes and users should prevent themselves from providing these kinds of information to secure their privacy.