Who's right here? Is "so" really the new "um" -- and is that wrong? Turns out, they all may be right. "So" has many uses, according to this analysis in the New York Times. And, as with any term of art, you need to think through your intent in using "so" to make sure it's working for you and not against you:
- As a logical connective word, which is how software engineers in Silicon Valley began using it (and, many believe, how it came to dominate the start of a sentence). It suggests authority, and indicates an explanation is coming, which is why scientists may be using it.
- As an empathetic connection, indicating that you've chosen what you're about to say because it's relevant to your listener, as in, "So it might be helpful to know that...."
- As a pause to think. If so, it's acting like an "um"--which, by the way, is a normal part of speech. But repeating one time-buying phrase like "so" over and over causes your audience to start counting (and it's too short to buy much time to think).