What type of message spurs people to comment on planning matters?

Salt Lake City does a wide range of "civic engagement" measures in its planning and management of government.  Even putting out flyers with pull off tabs and yard signs and banners in parks and other public facilities about the annual budget.

Yard signs are used a lot in planning engagements.  But there are also mailers and other techniques employed.

I will say they are good about surveys and such, not so great about providing opportunities for detailed comments.

I was struck by the signs for the 2100 South road planning engagement, because one side of the sign is positive ("Help with the future of 2100 South") and the other side is more negative ("Tell us what's wrong with 2100 South?").