What does "shout from the rooftops" mean?

Announce publicly, as in Just because I won first prize you needn't shout it from the rooftops. This term alludes to climbing on a roof so as to be heard by more people. A similar phrase, using housetops, appears in the New Testament (Luke 12:3): “That which ye have spoken ... shall be proclaimed upon the housetops.” [c. 1600]