When sent a form of communication – be it an email, an SMS, an instant message, a written letter, a pigeon, a Morse code or smoke signals – it is always good manners to respond. Regardless of whether there was a direct question involved.
The same implies for when someone is addressing you with an issue of some sort. Maybe they want your opinion on something, maybe they are asking for your input, or maybe they simply want to share their experience with you. But in all cases, they expect that you will respond in some sort of way.
Otherwise, if you don’t even have the courtesy to nod in acknowledgement that you are registering what they’re saying, it is easy to misunderstand or rather, conclude (either rightly or wrongly), that the other person is simply not interested.
If you care enough, you find the means, the time, and the way to respond.
The French have even globalised a polite abbreviation for it – Répondez S’il Vous Plait (RSVP). OK, you might not really want to respond to something, but it is merely polite to simply acknowledge receipt of the communication and fire up a minimum five-word response. It takes up much more of your time trying to edit a photo to upload on social media, or scrolling through social networking sites.
It is a shame that in the so-called digital era all this technology has in fact made us so anti-social.