The lecture taught me that anything you post online can be tracked. However, my digital footprint is pretty good because my twitter account, for example, does not have my real full name on it so that future employers don’t google me and see a bunch of bad memes. I was always very careful so that I don’t attach my full name to many accounts online because I know that stuff I posted in my teens may not look so good when I’m older.
I think that having a digital footprint can be important if you post serious job related things. However, if your social media accounts are more personal, it’s better to have privacy settings and not attach your real name.