A comedian is posting reviews on Yelp that are part of a bigger scheme, Grub Street has discovered. Instead of writing simple reviews for the places he visits, Gregg Gethard a.k.a., “Karl G.” writes stories that are part of a novel. Karl G. is an actuary who works in risk management for a parking-garage, and he shares his life’s story on Yelp while reviewing various places in Philadelphia. In addition to offering details about the places he hangs out in, he’s talking about his divorce from Cynthia, his kids, his wife’s new love, his new relationship to Tonya M. – a woman who spent 18 months in prison for voter fraud – and his new cat “Dog,” among other things. “Taqueria