>> Never have so many people expressed so much with Post-It notes. Ad agencies in lower Manhattan grabbing each other's attention and impressing onlookers with a playful Post-It note war. It all started with an anonymous hi, leading an employee from Havas Media across the street to respond. Now it's ballooned into an all out creative battle.
Adele lyrics and all.>> We'll see somebody do something and like we can do better. Because you know there is a lot of creatives in both places and they want to one up each other. So it's like back and forth like that.>> The bat signal, Spider-Man and Snapchat symbol in three inch paper squares.
With as many as five agencies now involved.>> Everything's so digital these days. So it's kind of funny that it's a kind of non-digital thing.>> Still, the work is so popular, it is being shared on social media with the hashtags postitwar and canalnotes in reference to the city street where it's all going down, or up, as the case may be.