i live in the area and am skeptical that ANYONE uses the full name in day to day contexts.  the dominant newspaper (salem news) still uses "manchester", the police department answers their phone "manchester PD", high school students refer to "manchester high".

i understand the urge to distinguish itself from the much-larger manchester, NH, nearby but IMHO this was really just a change on paper.  the only time i hear anyone affix "by-the-sea" in day to day speech, they also add "technically".  as in "i live in manchester...well, manchester-by-the-sea, technically".

i think the article should be reworded to reflect that.  that "most locals use..." stuff doesn't pass my BS meter.  but i'll wait to hear what others think.  209.172.25.215