A plugin is a kind of Joomla! extension, in fact the smallest building block of a Joomla site. Plugins provide functions which are associated with trigger events. Joomla provides a set of core plugin events, but any extension can fire (custom) events.

Many people think of a template as their website, but that is an incorrect way of seeing templates. Templates are used for providing a layout and design within which all of the pieces of your Joomla site come together.

Despite claims to the contrary Joomla 1.5 does have an ACL system. It may be rudimentary but when fully understood can be very useful.

Technically, content is every piece of text and media that is distributed/displayed via your site, whether that be in the component, module, mambot/plugin, or template. In Joomla, when someone says content, they are probably referring to the core content component and the content items that are entered into that component and displayed on your site.

Mambots where the ancestors of current version Joomla plugins. Mambots were introduced in Mambo and offered possibilities to add plug-in logic to your site mainly for the purpose of manipulating content. As the smallest Joomla extensions, they where smaller or bigger chunks of code executed upon being triggered by specially formatted keywords/signal words inserted in the various places of a Joomla 1.0 site.

One of the most easy ways to make your Joomla website faster is to leverage Joomla browser caching. This is one of the high priority tasks recommended by Google to make your website load faster.