How has Facebook been used negatively?

• Without doubt, there is much evil that takes place on Facebook. Some Muslims are interacting with members of the opposite sex. Parents who are normally worried about their children mixing with the wrong crowd on the streets are unfortunately unaware that this could also take place indoors in front of a computer. This ‘free-mixing’ which takes place on Facebook could be a path that leads to Zina, something the Holy Quran has strongly warned people against. One particular feature, ‘poking’ the use of which is only to alert someone else that they have been ‘poked’ could be interpreted as if someone is being physically ‘nudged’ or ‘eyed-up’ – this frequently takes place between members of the opposite sex.

• Many people use Facebook to promote illicit music by posting YouTube videos of music artists – a culture which Muslims should stay away from because every evil that you preach, you will incur the evil deed if someone else watches it and is inspired by it.

• Facebook is used by some people to post useless information such as their life diaries or some useless activity they did in the day – words which have no benefit. Sometimes a person reveals his sins on Facebook in a manner which he doesn’t consider it to be a sin; it is said that Allah will not forgive a person who Allah had concealed his sins which he did in private but he exposes them by telling others. In the opposite end, a person may reveal his good deeds on Facebook and will lose the blessings of that deed.

• We also have to ask ourselves how much time were spending on facebook and other social networks. Are we missing Salah and neglecting other important duties in Islam because we’re spending excessive number of hours on facebook daily? Yes facebook can be used as a da’wah tool, but when it effects your duties it will lead to being something that is haram to use!

http://www.onislam.net/english/shariah/shariah-and-humanity/shariah-and-life/451858-fiqh-of-facebook.html