The first poster is an overall campaign design - promoting the idea of sharing through handwritten text, but also incorporating the idea of the post-it:
The faded-out blocks will be real post-its, and the only printed elements will be the the logo, strapline, and the social media links. The post-its may (or may not!) have things written on them, as if people are already sharing - equally I may investigate simply leaving a pen by the side of the poster, to thoroughly make the most of the interactive element. I am aware that the poster as a whole needs a touch more info, but this is where I'm at to date.
The second poster is more finalised... But not quite ready to print. It promotes the idea of writing on the post-it, and sharing it with others:
It's meant to look like a zoomed in image of a wall full of post-its, with the info and images contained in the confines of a post-it shape. In the white square will be a block of post-its - so that people can grab one and start writing. Again, the info on this may need tweaking, so that people get the idea.