If you, like me, have made various assumptions of the Facebook lifestyle, I highly reccomend the reading of this post by Jonathan Sherwin.
Christians, I believe, should keep watch on their online selves. Not just on what they post, like and comment on, but also on what feelings they are having by just viewing other people’s pictures and reading what they say. Emotions are very important, and if you’ve been feeling un-Godly ones, be careful! Do not cause your eyes to make you sin. On the first jealousy, greed or anger feeling you have because of something you’ve seen, you should close the web page, pray about it immediately and ask God for help. If need be, abstain from Facebook (or whatever social networking page it is) for a while until the Holy Spirit tells you you’re ready to use it again. I believe God can use Facebook for the good, but we, as Christians, have to have our full armour on so that we are prepared for whatever attacks our integrity.
There was a time when I was feeling so bad because of Facebook that God told me to shut down my account, have a time out (of a few months) and re-do everything later, really thinking about who to add and being very wise with my time on it and what I clicked on, read or felt. It has done me much good.