The activity formatter on a form is a great part of ServiceNow. As long as it’s added to the form, and the table is audited, you can get a quick glance of the most important updates.
However, my only issue with it (and it’s my issue with all formatters), is that you can’t apply an ACL to it. For some users, I don’t want them to see it at all, but I don’t want to have to create a custom view just to hide it.
What I did therefore was found a way to apply ACLs to the formatter. This little trick can be used on all formatters.