Contributions (a.k.a Add Ons, a.k.a Modifications) are code snippets or code modifications designed to alter or add functionality to osCommerce installations. The osCommerce add on area contains hundreds of contributions created by osCommerce community members and are available under the GNU General Public License (FREE TO USE). There are also commercial add ons available from private companies and individuals that integrate into osCommerce stores. These commercial applications are usually licensed under EULA - End User License Agreements and can be found by looking at Community Forum Members ‘about me’ pages or by checking your favorite search engine.
Although a vanilla installation of osCommerce could be fully functional and ready to make money in no time at all, without the available contributions the base functionality will leave the store owner lacking in performance, reporting and marketing tools.