Each CMS contains a set of features the author considers useful, or chose to include.
If a significant feature is missing from the CMS you select, an addon product may be available that can provide that function.
A vast selection third party products have been developed providing extra features that range from very useful to "just for fun".
For CMSimple, addons might include an image gallery, a banner advertising campaign, RSS news feeds from other sites, or some other feature that would add value to your site.
On our site we have enhanced the standard CMSimple features by adding multiple RSS news feeds to the Latest Industry News section.
Some products work better than others, so evaluate them using our how to select a product checklist.
Features can be added when your site is originally created, or added later, once visitor feedback is available.
Some synonyms for addon are accessory, accessories, addons, add-ins, add-ons, extensions, plugins, plug-ins, snippets, and widgets.