Web consulting company Modem Media named consulting veteran Marc Particelli as its new chief executive. Most recently a partner with equity firm Oak Hill Partners, Particelli joins the Norwalk, Conn.-based company immediately and replaces co-founder and current CEO G.M. O'Connell. O'Connell will remain on the board, and Particelli has been named to the board. Before he was at Oak Hill, Particelli was a senior partner with management consultancy Booz-Allen & Hamilton.