We all have friends online who we don't really know very well, and many times have never met in person. As such, it's unlikely we would know all of our partner's Facebook friends—to include coworkers, colleagues, college friends, etc. However, when lots of comments and likes start coming in from someone new—and usually just one person—it's a red flag. if you start reading little quips and inside jokes on their Wall and you have no idea what they are talking about, something is amiss.