system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 Bostonians and "Sweet Caroline"

What's so special to Bostonians about this song?  I heard of them singing it after the capture of suspect #2.
gpt
If memory serves, sometime in the late 90's it was played at Fenway as a kind of inside-joke congratulations for an important family member who had recently had a baby girl that they named Caroline.  It got used more often but still not consistently.  Over time it simply got used more often as the fans reacted positively to it.  It became ingrained into the Red Sox personality and obviously permeated throughout Boston in general.