(Sharecast News) - Marketing automation and customer engagement outfit DotDigital's chairman Richard Kellett-Clarke stood down from the group on Wednesday, effective immediately.Kellett-Clarke offered his resignation to the board, which promptly accepted it, due to undisclosed "private matters" in another of his directorships.DotDigital founder Tink Taylor will take on the role of interim chairman until such time as a full-time appointment can be made, assuring investors the board will accelerate its search for a new chairman and provide an update as soon as practicable.Chief executive Milan Patel said: "I would like to thank Richard for all his tremendous efforts at DotDigital and all the help and support he has given the company and me in the past eight years."As of 0845 BST, DotDigital shares were down 1.59% at 93p.