Originally Posted by CIVMatt

* Setup multiple web sites
* Setup complex membership fee structures, including trials, special offers upon cancellation, partial vs. full memberships, and more.
* Manage your web sites members - add, cancel, refund, view transactions, etc.
* Completely customize your signup pages
* Customize e-mail receipts
* Manage your affiliate programs
* Setup complex payout structures with or without tiers, bonuses, etc.
* Setup a marketing center for your affiliates to use when building their campaigns to drive traffic to your site
* Send out targeted e-mail messages to your members
* In-depth reporting

intresting, I'd like to hear if anyone is using them