Economist.com’s top techy and Telegraph Media Group’s digital chief are replacing Guardian Media Group (GMG) online topper Simon Waldman as joint chairs of the Association of Online Publishing. GMG digital director Waldman announced his departure from the industry umbrella group ahead of its annual conference earlier this month. We already know Telegraph counterpart Alison Reay was to be one co-chair; today the AOP said Economist chief information officer Mike Seery would join her. Reay, though, will step down again in September 2009; Seery will join next April and the two will overlap until her departure. Release.