Social Resharing, What You Need to Know.
Resharing content across social channels is common, but is it legal for a business? The easiest way to get explicit permission is to comment a thank you to the person who shared, and then ask for permission to reshare.
When someone shares to your social account by tagging you or using your hashtag, this is often considered implied consent. Implied consent is acceptable, but a rather grey area.
If you run a sale or promotion, and feature their content, and earn revenue, you could be in some trouble. It is always considered best practices to incorporate a guideline for sharing, resharing, tagging, and the use of hashtags into your social media policy.
A fantastic app for easy resharing on Instagram is the Repost for the Instagram app (available for Android and iOS). Facebook and Twitter are very easy to reshare, using the camera icon and placing the handle after is a popular way to give credit.