This postcard shows Rockport harbor, with its two fishing shacks — the closest the famous Motif No. 1 — and the breakwater in the background.
The publisher of this postcard, The Rotograph Co. of New York City, was in business only from 1904 to 1911. This postcard has a divided back, which indicates that it was printed after 1907, the year the U.S. postal service first allowed divided-back postcards. I estimate it to be from roughly 1908.