2.19.
Rich ecosystem of free add-on products
Up one level
Plone has an amazingly rich ecosystem of add-on products available. Need a message board? How about a plugin that lets you authenticate against an SQL database? Need support for that obscure bibliography standard in your site? A ticketing system or an issue tracker?
All these, and more are among the over 700 add-on modules available for Plone in the Add-on Products area on plone.org. All of these add-ons are free, and licensed under open source licenses, which means you can freely use them in your site.