With the Web site Yelp still responding to allegations by San Francisco businesses that it manipulates the prominence of positive and negative reviews, some Chicago merchants are adding to the heat.They allege that Yelp representatives have offered to rearrange positive and negative reviews for companies that advertise on the site or sponsor Yelp Elite parties.Ina Pinkney of Ina's restaurant in the West Loop said that last summer a Yelp salesperson offered to "move up my good reviews if I sponsored one of their events.