This is an American World War 1 poster.  I found this poster particularly interesting because your instantly drawn towards the word 'Food'. So you know without a second look what it's about. 

Underneath it says 'Keep the Home Garden going'. Food was much needed for soldiers and starving civilians. The colours are very much in blocks to seperate the sky, crops and the ground. I think that i could relate some of these aspects to my own ideas for my chosen social media. Facebook.  You can tell by the way of the people's stance with one foot in front could suggest that they are going in the right direction of keeping the crops coming for the soldiers. Also the 'Keep the home garden going' part can suggest that the food is being produced they just need to stick with it and maybe get other people to participate with this too.