Filtering contacts is useful for many things. You can view contacts that just meet certain criteria as well as sending to these filtered contacts. A good example of this is viewing a list of your unsubscribes

To do this if you go to contacts > contacts. This will open your main database of contacts. To view unsubscribes you need to apply a filter. To apply a filter, click ‘filter contacts’ and this will open up a pop-up window.

On the pop-up window, you need to set up one filter rule. The rule is all contacts that have an activity ‘unsubscribed from a list’ and this unsubscribe is from any list. See the rule below.