Pinterest is doing really well - we're talking $5 billion valuation-level well. And to cement its status as a mega-success, the site has scooped up two former Apple execs to lead engineering and product design. First up is Michael Lopp, who worked on Mac OS X before moving to software company Palantir. As head of engineering, he'll help scale site infrastructure and lead product development teams. On the product design side, Pinterest's appointed Bob Baxley, who worked on Apple's online store. His official title will be head of product design and research.