Well you should see this answer and all the questions usually have a list of all the answers if you click on them. If you give an answer you will get an email of every answer after yours until you click on the link to stop notifications.

Do you mean in the Photo Questions section of Houzz?
Those questions are sent to the designer, architect, or photographer who originally uploaded the photo, but it is up to them to decide when and if to answer. Some very popular designers who have many photographs of their work on Houzz get overwhelmed by hundreds of inquiries and simply can't answer them all. Others don't always know the answers, for example if the photo was posted by the architect, but the question is about a sofa in the photo chosen by a different designer or the homeowner. So it is a bit hit and miss whether the Photo Questions get answered or not.