LOL. Just for fun I searched it....phone numbers were not top results, street addresses were. Even making it Pleasant exchange 6-3318 didn't yield phone number results.
The number dates back to at least the 1950's. Back then, Massachusetts was just two area codes, 617 for the eastern part and 413 for the western part. (Now it's at least 5 for land lines, plus more for cell phones.) We only had to dial 7 numbers, not ten. The first two numbers were given words to represent the first two of the seven. P in PLeasant was 7, and the L in PLeasant is 5. Another in use around here was SWift (79). This was second nature to locals. You would say "pleasant 6 3318" and they would intuitively write PL6 3318 or 756-3318. I still have a very heavy, black desktop rotary telephone with NON-detachable cords and "PL6-3318" hand written on the paper center of the rotary dial, covered with an acetate protector. It was written there by my maternal grandmother who died in 1966.
The number changed from the 617 area code to 508 back in the 1990's. It may be in use by someone again, so don't go calling it, please.