AppNexus on Monday announced the appointment of Jonathan Hsu as chief financial officer and chief operating officer. Hsu was formerly CEO of 24/7 Media.“Today, I’m thrilled to announce that Jon Hsu is joining our team as COO and CFO,” wrote CEO Brian O’Kelley in a company blog post. “Jon is one of the few people with CFO experience at a public ad technology company, but more importantly is one of the best executives in our industry.” The company has shaken up its leadership team in other areas as well, starting with the promotion of Geir Magnusson to chief technology officer. He was previously AppNexus’ VP of engineering. Michelle Dvorkin has also been promoted, to SVP of people. She will manage the company’s human resources department, per the release. Additionally, Casey Birtwell has been hired as SVP of strategy and operations, a new position. He joins AppNexus from Avaya.