It's poison for those too immature to understand that what they say on social media reflects on them (and sticks with them, it can become permanent - I've saved many posts to pdf format on my computer). It's antidote for those mature enough to use it that way.
We need to remember that social media is not a one-to-one conversation. It's a one-to-many (and those many include people you may not know) conversation.
Discernment is not something everyone has a good grasp on these days. But there is always hope that each of us learns and gains wisdom along the way.