In the last few years, I've noticed a growing usage of the word "so" to begin a sentence, especially in the context of higher education.
Interviewer: "What is the nature of your research"
Researcher: "So, what we wanted to find out is..."
It seems to be a replacement the word "well", or, more informally, "ok". Has this usage of the word been around for a long time and I'm just now noticing it? Do you think that is a valid use of the word?