If you want to get things moving at a meeting or in an online forum, start discussing what to order for lunch. Even the most reticent attendee has something to contribute.
Same thing when you start discussing the logo for your new venture, or what to call the subcommittee on committees… Have you noticed how many people are willing to weigh in on redecorating your office?
It's so easy to speak up on the things that are trivial, defensible, matters of taste. So easy to imagine that you're a valuable contributor because you're willing to share your personal taste on a matter that's beyond reproach.
If I want your opinion, I'm going to want it for something where you might be wrong, for something that actually makes a difference and most of all, for something where you are putting yourself at risk. Not lunch.