I do agree that may be advantages are more but it depends….. what kind of data and information you are putting into these websites. Sometimes it may create trouble(s) for an individual, while everything is public and website knows most of the things about them. Even if you put these data inside the application's private section, yet your data is not 100% safe and secure. I am not against to these websites but want to explain that how it may create troubles for an individual.
I have made a small kind of research and find a list of the social networking sites disadvantages / threats:
1.) Everything Is Public – The nature of social networking sites is that they are ‘well’ social, so things get shared. And one small mistake can morph into a public relations nightmare. Specially in case of an individual (Male / Female).
2.) Negative Publicity – People really like to use social networking sites as a place to express their frustration and disapproval of a business that they feel has wronged them in some way. Being on the receiving end of this negative publicity can have dire consequences, so it’s important to keep your customers happy and respond quickly to any issues that someone does publicize.
3.) Time Consuming – Social networking sites can suck you in and before you know it you’ve spent hours looking at pictures, videos, and reading clever posts. It’s important to remember when using social networking sites for business purposes that you stay on task and only spend time on the things that help your business. ‘If it doesn’t make money, it doesn’t make sense [cents]!’
4.) Data Insecurity & Incorrect