Very popular extensions for Joomla 1.5 that we have proudly developed from 2007-2013.
Documentation is available here.
Multi-seller eCommerce shopping cart. Create B2B, B2C, C2C, Mall, personal e-shop, ...
Invoicing/Billing solution. Can be used as payment gateway for any component.
Restrict any part of any site (component) to access on payment basis.
Send private messages between users.
User manager. Extend registration form with additional fields.
Social Networking tool to create sites like MySpace, Facebook, Мой Мир, ...
Display reports for different components in flash diagrams.
CCK (content construction kit) extension for Joomla. Create everything that you can imagine.