We present the design and evaluation of MyPosition, a public display in the form of a large projection, featuring an interactive poll visualization. MyPosition aims at facilitating the deliberation and comparison of individual opinions on locally relevant topics in an opportunistic and engaging way. We evaluated MyPosition in an in-the-wild study and demonstrated that the engaging nature of the installation was effective in enticing public discussion. We found that (i) the increased identifiability of users positively impacted the engagement with and the social debate around the installation, however lowered the actual polling rate; (ii) people submitted their personal opinion instead of playing around with the interactive features; and (iii) the display led to considerable discussion as well as nudging among people, in particular in zones beyond the interaction area in front of the screen.