how to use facebook and what is its benfits?

[Andy]

Register and start using. Benefits are increases your self esteem if you have none or a low self esteem. Very suitable for narcissistic folks where you keep uploading your photos every day and admire along with friends and family. Can be used to slander your enemies or write love songs for your love object. You can also stalk 24 hrs and harass/bully. You can be mistaken for a criminal when a crime happens, because FaceBook is the first place where law enforcement and nosy public look for.

You can make plenty of fake/fairweather friends who will pry/use for their purposes. Having numerous fake friends increases your popularity though.