We've simplified things a bit.
You can become an approved (~permanent) member by leaving at least ten insightful comments on other member's poems, OR you can instantly upgrade
for as little as $2 with a regular membership
Once you have posted at least ten comments, they will be reviewed by site moderators and approved, held until more comments show up, or disregarded, depending mostly on your attitude and engagement with others.
The "Postcard" membership refers to a program we ran for over ten years in which members had to send in a mailed postcard to attain permanent status on the site. Both for practical and environmental reasons, the postcard program was retired in early 2012, with this alternative path to approved membership taking its place.