Cambridge-based Jumptap, which places ads on mobile devices that are targeted to reach interested customers, last July hired Yahoo (Nasdaq: YHOO) veteran Frank Weishaupt for its newly created position of COO. Weishaupt, who had most recently been VP of advertising marketplaces at Yahoo, had worked at the company from 2001 to 2011. The move might be seen one of Jumptap's recent steps toward an IPO; CEO George Bell had said earlier that month that Jumptap was planning an IPO for as soon as spring…