World Milk Day
You may have spotted Cadbury's new Dairy Milk poster, which is cleverly done, showing you how much of the poster would be milk if it was the same size as a chocolate bar (if only).
Shortly afterwards a Nestle's Milky Bar poster popped up nearby, seemingly in response. The first rumblings of a chocolate bar war perhaps?
Or - more likely - as I found out a few days later, a reaction to World Milk Day? It seems too much of a coincidence not to be, seeing as they appeared around the same time. But no mention in the small print. And not a hashtag in sight!