Beginning a sentence with the word "so"
Sometime in the first decade of the 21st century in the United States, it became common to begin a sentence with the word "so."
It doesn't have any semantic meaning it's just tacked on.
I just figured it out. The modern tendency to start a declarative sentence with "so" derives from the suppression of "um" declared unacceptable for schoolkids for many years.
It seems like it's a way of softening a direct statement. An interviewer asks the young professional about the new product, and she tells him "So what this does is blah blah blah."
It may or may not be interesting that this tendency developed during a time when the United States was conflicted about the 2003 invasion of Iraq.