Your digital footprint is not just the things that you post on different social media sites. Your footprint also includes online newspaper articles and photographs and things that other people post that you may be tagged in. If you (or your team) win awards, your name and photograph could be linked to that. If a friend posts a picture of you in a silly pose, that may be part of your footprint, also.
One way to get a sense of what your digital footprint is already is to do something called a "vanity search." This is when you Google your own name to see what other people see when they search for you. There might be nothing. There might be a few things. There may be things about people who have the same name as you. It's worth knowing what Google can find about you, because employers will search for you and so will the universities that you apply to, when you are in grade 11 and 12. I've even searched out potential baby-sitters to see if I would trust them as a person to look after my children.
Think about what kind of a digital footprint you would like to have in a few years. What kinds of things would you like to see when you look yourself up on Google. Would you like newspaper articles or videos of interviews? What kinds of things do you hope you'll have created that other people will see as examples of what you do well? What awards might you have won and how would those show up- would there be photographs or links to webpages of the sport you play? Will your Facebook, Twitter, Instagram, website or Electronic Portfolio be there?