Actually i have noticed it for a while now, and have come to the conclusion that the speaker often uses "so" when they don't intend to answer a question or criticism. I almost started a thread about it, but thought that maybe it was just me.
I was listening to a set of interviews on a particular subject when this last came to my attention. The interviewer asked one of her guests why she had taken a particular position. The woman replied: "So . . ." and then made remarks pertinent to subject, none of which answered the question. The interviewer persisted, and just at the end of that segment, she finally got the woman to acknowledge that she strongly felt she was right, but couldn't offer any data.
She then turned to her next guest (opposing point of view), and roughly the same thing happened. After stating her position, and being asked by the interviewer upon what basis she had come to the conclusion, the woman began every reply with "So . . . (a pause)" and made remarks pertinent to the subject, supporting her position, none of which were an answer to the question. The inteviewer completely failed to get even a ghost of an answer from this second woman.
Third guest is Mr. Responsible Government Representative. The first few questions go well--he's got detailed answers and all the data at his fingertips. Then about question five or six, roughly "What enforcement powers can you exercise?"--there was no response at all--dead air, a big no-no on radio. So the interviewer asks the question again, and Mr. Responsible Government Representative pauses for a moment, and repeats one of his previous replies, prefaced with "So . . .," which is pertinent to the subject, and not an answer to the questiton. This happens a couple of times, and finally Mr. Responsible Government Representative, à propos
of nothing specific which the interviewer has said, says: " So . . . there are 1200 facilities in this country, and I have 22 staff." The interviewer then asks him if in fact he has no enforcement powers, and the facilities are in effect policing themselves. Long period of dead air, then "I have no comment." After a brief further period of dead air . . . "Well, that's all we have time for today--i'd like to thank my guests . . . " Show's over.
Now i know i've carried this much further than your comments. However, it seems to me that this little trick of speech often signals that the person responding does not intend to answer the question.
Finally, an odd case of this later in the day. A prominent entomologist is being interviewed, and she describes two examples of an insect which lives, usually in the understory of a forest, but the latter example thought to be evolving even as they're being studied. The scientist describes how this latter group of the insect have taken to colonizing dead trees at the level of the forest canopy. The interviewer asks her what effect this has on the health of the trees. There is a brief pause, then she says to him: "So . . . this second group has begun to colonize dead trees
at the canoply level . . . "
This was also not an answer to the question, but for quite another reason. Within a few moments, the nickel drops for the interviewer.