I joined because I wanted to support a great community. I know that its more supporting to share information, which I try and do as much as I can, but some times it takes a little money as well.
For me, the membership has been worth it. I've learned SO much about backpacking, camping, fishing, gear, techniques, geography, ultra-light backpacking, home-made gear, cottage industries, etc since I became a member. Obviously you can learn about almost all of this from the forums for free, but I didn't feel right just using leeching the service and experience of others.
I do like Todd's idea of replacing the old BPL shop with a mall of items from all the cottage industries that are part of this community, that would be great! It gets more traffic for BPL, they get to retain a shop (and possibly sell small things here and there if they want), they don't have to spend as much time or resources on the shop as it is mostly handled through the cottage shops, cottage shops get more attention and recognition, product reviews can be more centralized and easier to find, and boosts cottage shops so that they don't die out so easy and are able to compete with the larger companies.
I think its a win/win and a natural relationship between the two that should definitely happen.
I also think that it would be great if you got some swag for buying a membership. Maybe a sticker or something for a year membership and a patch or something with a lifetime membership. Just an idea (that has probably already been stated previously in this long thread)