The idea and function behind brainstorming is to gain a large number of diverse ideas or solutions related to some goal or problem. Brainstorming also serves a second function of bringing people to express themselves without fear of being criticized. Do not criticize an idea.
Every idea is acceptable, even if it sounds silly.
Re member, we're trying to gain a large number of ideas. Criticism tends to shut some people up. Piggybacking is picking up on an idea and altering it a little, or taking something away, or even expressing the exact opposite. You'll be surprised to find that the screwiest thing you ever heard can turn into a beautiful idea just by applying a little piggybacking. As a leader, you should keep the brainstorming storming.