Content Disclaimer Plugin
Content Disclaimer Plugin is a content plugin for Joomla!, the initial and most simple version of Content Disclaimer Popup. It was also the first kind of extension for this purposes in JED. Initially it was working with no limitations in all Joomla! versions, but since Joomla! 1.5 it needed a refactoring for showing itself when there aren't Joomla! articles present.
See this post for more info about this.
In short, the disclaimer can't be displayed if there isn't, at least, one standard Joomla! article in the front-end. For doing this through a Joomla! content plugin, it would be necessary to do a long and heavy query to database each time a page is loaded, something non-viable for big sites and dirty for small ones. Another solution, the one I chose, is the extension's refactoring, doing a system plugin or, as in this case, a module.
So if you have a site with standard Joomla! articles, you wouldn't have any problem with the plugin. But if your site are not displaying Joomla! standard articles in some section, (this means a section showing only modules and menus, shopping carts, product sheets, contact forms or any component not integrated with Joomla! articles) and you want to display there the disclaimer, your case will be perfect for downloading Content Disclaimer Module in lieu of the plugin.
You can download this plugin for free, but it won't include improvements, updates (only vitally necessary) or any kind of support queries, included email queries. If you need support, regular updates and improvements, you need a subscription. After purchasing it, you will also be able to download the module.