It’s late. You had a bit too much to drink or maybe you’re just irritable because of fatigue, but you decide to log into Facebook and respond to your ex’s post about her new relationship or you really let your boss have it for making you stay late. You let your true colors show — and they are not beautiful.
You wake up in the morning and your phone is blowing up from notifications about your post. You promptly delete your post, pretend it didn’t happen and continue on with your day.
That post was deleted and never happened … right?
Wrong. Even if you delete a Tweet or remove a Facebook post, it was still read and has been archived.
When a user posts on another’s wall, the receiving user gets an email with the text of that post. This is proof or evidence. If you tweeted an ill-tempered tweet — or any tweet actually — it has been archived by the Library of Congress. If someone follows you to his or her phone, your angry tweet is saved as a SMS text. 
Suppose what you said online could be considered threatening; if someone was truly offended and wanted to report you, saving the evidence is as easy as a quick keyboard command to screenshot your post.
I know this latter archive technique because I used it once. Someone I knew threw water balloons at my car and put a Frosty on my windshield. I was unhappy, so I browsed Facebook and found the culprit because they didn’t think before they posted. I “screenshotted” what she said before she deleted it and made her clean up my car or else I would get police involved.
Suppose an organization begins to delete negative posts on their page, there will be some backlash. (Unnecessarily vulgar and explicit posts are fair game for deleting, especially if stated in the About section of the page.) These posters will ban together, spam the page and continue to do so until the organization addresses the problem and fixes it. People don’t like it when you ignore their criticisms, let alone delete them.
Deleting posts show weakness either way. If you said something dumb, take responsibility for it. If someone posts a negative critique on your page, respond to it in a mature way.
