Dungeons & Dragons Insider (DDI) is Wizards of the Coast's method of digitally delivering periodic content and information about Dungeons & Dragons to the game's players.
DDI was announced at the 2007 Gen Con as a subscription-based electronic supplement to Dungeons & Dragons. The demo included a short video of a virtual "dungeon" (called the Game Table) in which some D&D adventures take place, containing virtual miniatures based on your character as created in the Character Visualizer (a 3D full-body portrait program).
Currently DDI subscription includes an online character builder (requires Microsoft Silverlight), archived Dragon and Dungeon web content, and a compendium of rules elements for the 4th edition of Dungeons & Dragons. Additionally, a beta version of a monster builder (as part of the Adventure Tools suite) and the Virtual Table have been released.
Presently, it is unclear if the Character Visualizer is still slated for completion as originally advertised. This has caused some degree of backlash within the customer base, as this tool (and the currently-in-beta Virtual Table) were scheduled to launch when the 4th edition core books were released mid-2008; an additional source of anger is the litigious approach of Wizards of the Coast towards third-party developers who create tools to fill the gaps left by these unreleased tools.
August 2014 subscription renewal emails from Wizards of the Coast indicate that DDI subscription will no longer include new issues of Dragon and Dungeon magazines (only archives), and the online resources will no longer be actively supported.