According to the stats collected by Mozilla, around 85% Firefox users have at least one add-on installed. This is really big, and reconfirms that the Add-ons are the real power of Firefox.
Moreover, only one-third Chrome users use extensions, according to an estimate of Chrome team in December 2010.
Future of Firefox Add-ons
Firefox and its add-ons are usually blamed for consuming large amount of system resources. Mozilla developers are working on this issue and several improvements have been already integrated with the Firefox. Mozilla has also introduced multi-process for plug-ins to increase stability and performance.
Another notable feature related to Firefox add-ons is the new Add-on SDK (Jetpack). This tool enables developers to develop add-ons easily using easy-to-use APIs. On the other hand, the Jetpack platform ensures less buggy add-ons by following a standard way of accessing resources.