People on FB that think they know everything and consult other FB people on religion, politics and other topics. In reality these people really don't know shit.
A Facebook know it all..... " John, the Bible never said anything about homosexuality, let me lecture you more on shit I don't know about.... "
by Alan Prokop December 23, 2013
"Facebook know" means to know someone only through Facebook. You've never met, talked or texted, but you know many details about each other through posts that appear in the other person's feed and replies to those posts.
by circlesofindecision January 28, 2017