I wonder if someone screencap it, and posted it on 4chan or someother similar image board or blog.
The guy should of set his Facebook privacy settings to private, or friends only. This is one of the disadvantages of having a Facebook fanpage to public, or having friends which are pranksters.
The only thing people are supposed to be doing in class, is learning.. not tweeting fbing or anything like that.. and yet, people are surprised by the fact that todays kids have only gotten dumber, and sadly, the equally stupid parents will only blame the teachers for this eventually..