There are 2 sides of the coin - consumer side (doesnt affect ME buying a knife), and a company side (company/brand image, openness, friendliness etc).
And owners\designers actually reading those forums shows a certain level of involvement.. Listening to your actual active client base is kinda important. Again its not necessary wasting time on forum chat.
The Giant Mouse product launches on instagram are a perfect example how it should be done, imho.