I think you're confusing the terminology. A "neck beard" is a beard that goes around the neck. A "neckbeard" is a male, almost always a megamayo, that has terrible hygiene, bad social skills, enjoy anime and/or my little pony, mountain dew, doritos, katanas, dressing in trench coats or anything matrixish, tip their fedoras/trilbies at m'ladies, usually have blind faith in atheism and maximum/communism/socialism, are euphoric through the enlightenment of their own intelligence, think they're always right in internet arguments, and sometimes have full size anime girls printed on body pillows (aka waifus). This guy couldn't afford a pillow for his home made waifu so he had to photoshop it. The female equivalent is a legbeard. You can find out more from this subreddit that has this same photo on the front page right now. Reposting from there is basically cheating.