Facebook and Twitter sales teams will tell you that posts aligning with time relevant events (like national holidays, sporting events, etc.) receive the most interaction. But many times brands have a hard time using their owned media to support a general, non-brand specific message. It looks like this MLK day some brands caught on and even implemented this insight. Walmart took it a step further and promoted its post as ad.
Insight? - Even if a brand’s post doesn’t sell a product or promote one of its current campaigns, positing content that is interesting to users and results in a response is just as valuable. Possibly it is even more valuable, since the message connects with users on a more personal level and resembles and interaction made between friends on the site.