Seattle-based AdReady, a provider of Internet advertising services, said this morning that it has named Karl Seibrecht as the firm's President and Chief Operating Officer. Siebrecht joins the firm from Atlas, the online technology unit of aQuantive. The firm said that Siebrecht will oversee the firm's go-to-market strategy. Siebrecht has been at aQuantive since 1999, and subsequently served as an executive at Microsoft's online services division.