TWiki has a plugin API that has spawned over 400 extensions to link into databases, create charts, tags, sort tables, write spreadsheets, create image gallery and slideshows, make drawings, write blogs, plot graphs, interface to many different authentication schemes, track Extreme Programming projects and so on.
TWiki as a structured wiki provides database-like manipulation of fields stored on pages, and offers a SQL-like query language to embed reports in wiki pages.
Wiki applications are also called situational applications because they are created ad-hoc by the users for very specific needs. Users have built TWiki applications that include call center status boards, to-do lists, inventory systems, employee handbooks, bug trackers, blog applications, discussion forums, status reports with rollups and more.
The interface of TWiki is completely skinnable in templates, themes and (per user) CSS. It includes support for internationalization ('I18N'), with support for multiple character sets, UTF-8 URLs, and the user interface has been translated into Bulgarian, Chinese, Czech, Danish, Dutch, French, German, Italian, Japanese, Polish, Portuguese, Russian, Spanish and Swedish.
TWiki is primarily used at the workplace as a corporate wiki to coordinate team activities, track projects, implement workflows and as an Intranet Wiki. The TWiki community estimates 40,000 corporate wiki sites as of March 2007, and 20,000 public TWiki sites.
TWiki is implemented in Perl. Wiki pages are stored in plain text files. Everything, including meta such as access control settings, are version controlled using RCS. RCS is optional since an all-Perl version control system is provided.
TWiki scales reasonably well even though it uses plain text files and no relational database to store page data. Many corporate TWiki installations have several hundred thousand pages and tens of thousands of users. Load balancing and caching can be used to improve performance on high traffic sites.
TWiki has database features built into the engine. A TWiki Form is attached to a page as meta data. This represents a database record. A set of pages that share the same type of form build a database table. A formatted search with a SQL-like query can be embedded into a page to construct dynamic presentation of data from multiple pages. This allows for building wiki applications and constitutes the TWiki's notion of a structured wiki.
Dates of TWiki releases: