I just thought of this concept and I'd like to know if it is new or useful.

"Functional silence" is communication intended to carry as little information as possible. It intends for the beliefs of listeners to be changed as little as possible.

This is usually the same as regular silence. The difference is in cases where regular silence would convey the wrong message, such as when asked a question that one cannot politely refuse to answer, when unwantedly prompted to give a statement or when padding a short message because more words are expected. In these cases, a range of techniques is commonly used:

• Boilerplate statements. This is prepared words that have little or no relation to the subject at hand but are unobjectionable and usually express or imply an expectation of mutual respect or a mission statement.
• Distraction / subject change. This will usually be towards a superficially related subject. For example, many politicians when asked to give a prediction will instead talk about what they want to happen. Failing that, humor is powerful here. A switch to a shiny subject or an applause light works much better than a switch to a boring subject.
• Incomprehensibility. Use of lots of complicated words and allusions in quick succession in order to overload the listener's comprehension. Delivered with a friendly-seeming air of expectation that the listener obviously gets all of this, so the listener cannot ask without losing face. A classic salesman's technique.
• Repetition. Saying the same thing again in different words. This is most vacuous if it repeats something already said in the same conversation, but anything the listener already knows the speaker has said will do.
• Tautology. Statements that boil down to "if A is the case, then A is the case" without any explicit statement on whether A is the case. Sounds dumb when boiled down like this, but this is shockingly effective at convincing people that actual information has been shared.
• The median response. Expresses the most average (hence predictable, boring) thing that average people say in this situation. This does transport a bit of information, but will probably at least not be remembered.

These seem different and there are surely others I've forgotten, but I'd like to call all of them "functional silence" in order to emphasize how they all do the same thing. They all intend to minimize the sharing of information, while denying that intent.

"Functional silence" is inherently deceptive and probably a Dark Art. Excuses might be made for it in some situations, where it maintains a relationship despite a lack of trust or it covers up an uncomfortable lull in a conversation, but my intuition is that it is just Wrong. It is easily found, especially in political and corporate communication, and lots of other places once you look for it. But because denying its own nature is inherently part of it, and because I didn't know a word for it, I have found it hard to nail down. So I thought maybe having a word for it would help? Helps me, anyway.

I should say that I really think of functional Schweigen, but Schweigen is the German word for choosing not to speak, which English (being a clearly inferior language) doesnt really have a word for.