Any webcomic on Topwebcomics is able to join the active list. As a creator, all you have to do is click on MANAGE WEBCOMIC in the user menu.
On the far right of your series, you will notice a red circle where it says Active List. All you have to do is click on this circle to activate it. The circle will turn green with a check mark to certify your participation.
In order to stay true to the premise of an active list, you will have to reset your participation every month.
Hope it helps and we’re looking forward to seeing who will reach the top of this new list!