What is an extension conflict?
The non-technical explanation
Let's invent some feature "X" that exists within Magento In Magento only one extension per store may extend this Feature X.
- Extension A extends Magento Feature X
- Extension B extends Magento Feature X
There's no way for manufacturers of Extension A to know if anything on the store already extended Feature X and there is no way for manufacturers of Extension B to know likewise. Therefore a conflict exists. For MageRewards however, this page serves as an extensive resource for knowing what other extensions combined cause these compatibilities.
The technical explanation
An extension conflict exists when two extensions are doing a Class Rewrite (in each module's config.xml file) of the same Magento class.