Joining a political party whose principles you like is a great way to participate in our democracy at a grassroots level. So if you happen to like our principles, we'd love to have you as a member.
In concrete terms, your formal membership helps us to maintain our official registration as a federal political party (which currently requires we have at least 500 members who are enrolled to vote) and work towards official registration at state and territory level. It also is our best way of measuring our current level of support — more so than numbers such as website traffic or Facebook likes, which may indicate interest in us, but not necessarily anything more than that.
From your point of view, party officers are more likely to view your feedback and suggestions as constructive attempts to help us improve what we're doing if it's coming from a party member. Members also gain various formal rights within the party's internal democracy, as detailed below.