Elizabeth Cunningham makes a fantastic point below. Good or bad, you should never ignore feedback on social. Indeed, I think the same is true when someone comments on a piece of content you've shared.

They may be praising you, they may be disagreeing with you, they might even be disputing something, but the bottom line is: they are engaging, and what's more, they're engaging in the eye of the general public. More often than not, social interactions with your content will afford an opportunity to showcase your expertise and tell your  audience that nobody knows more about the topic in question than you.

Even if someone has left a short comment, why not answer them with a simple thanks? It takes no time and might help to foster brand advocacy. It's also a perfect segue to share additional content. I recommend signposting them to relevant downloadables that ensure you capture the person's contact details; turning them into a lead.