Site Cloner PHP Script
Bargain Hunter PHP Script
Job Hunter PHP Script
Site Login and Access Control PHP Script

Joomla has a wide variety of extensions available for tagging articles and having tag lists on any page. Joomla Tags is one such extension. The extension could need lots of extra configuring to get it working as desired. Personally, it has a consumed a couple hours on my end to get it functioning how I wanted it to work on a particular website. One issue that must be dealt with is that the tags seem to only work properly with all articles that belong to a category and section. Uncategorized articles do not tag; at least not very easily.