Mobile advertising is a strange beast. As more and more Internet users across the world begin using mobile devices -- instead of desktop computers -- as their primary means of getting information, companies are scrambling to perfect their mobile platforms.

Probably no company has made this transition more lucrative than Facebook (META -1.38%). When the company turned on the advertising machine for its mobile users, earnings doubled in a year's time and free cash flow jumped by 660%. That's astounding.

But not everyone has benefited from this move. Though Facebook is a major Internet advertising force to be reckoned with, it's yearly revenue is still less than one-seventh of Google's (GOOG 1.44%) (GOOGL 1.89%). One would think that, given this size advantage, Google would be benefiting from the shift to mobile as well.

But that's not necessarily what many Google bears believe. In fact, they think the move to mobile has been hurting Google. In the video below, The Motley Fool's Brian Stoffel gives investors -- especially beginners -- an explanation for this line of thinking and what he thinks of it.