The internet is a copying machine, and it's a job it does well.
All your social-media comments, shared photos, links and private messages are stored by social-media giants - some of which you can access at the click of a button.
But there is still a way to delete those embarrassing photos and musings you would rather forget.
When logged into Facebook, hover over your offending post's top right-hand corner.
Click the "pencil" icon to edit the post, then select "hide from timeline" or "delete".
To keep the post on your timeline for your eyes, hover over the people icon in the top centre of the post and select "only me".
Only those logged into your account can see the post and its comments from friends.
There are also options if you want your approved Facebook friends to see it, without it being completely public.
Simply deleting others' comments from your posts is possible by clicking the "x" on the top right-hand corner of the comment. You can delete your comments from other people's posts in the same way.
But you can't delete a post that has been copied from your page on to someone else's.
To delete a private message, open the conversation and select action, then tick the message you don't want to see.
You can tick off all the messages you don't want, including others' messages in the conversation, so they don't appear in your account.
They are still visible to others in the conversation. You can remove your copy of a whole conversation.
Similar rules apply on Twitter. Delete one of your tweets while logged in by hovering over the comment and clicking the rubbish-bin icon.
If it has been retweeted, the tweet will live on through other people's accounts, even after you have deleted your own.
You can protect your tweets by changing your settings so only those you approve will receive them.
Your future tweets will not be publicly available and no-one can retweet them. But previous tweets may still be publicly visible in some places.
- Sunday Star Times