Cclite is social credit and alternative currency accounting tool for LETS (local exchange trading systems) and other alternative currency management.
It is multi-currency and a single installation can contain many trading groups (registries). One registry is contained in a single Mysql database.
Groups can trade if they share a common currency. The mechanism for this is SOAP and REST.
There is a simple yellow pages system for offers and wants. There are also SMS, batch interfaces for data and RSS generation for ad feeds.