Extensions for enterprise wikis

You can see the extensions installed on this wiki on the special page Version.

Must have
Wikis using MediaWiki 1.21+ or installed after April 2013 should install Scribunto for the Lua scripting language. Lots of templates are now using this instead of ParserFunctions.

The extensions you need for basic functionality are:
 * Cite — Adds  and tags, for citations.
 * Math — Render mathematical formulas between $$ ... $$ tags.
 * ParserFunctions — Enhance parser with logical functions.
 * Gadgets — Lets users select custom CSS and JavaScript gadgets in their preferences.
 * InputBox — Adds already created HTML forms to wiki pages.
 * Vector — Improves on the user interface elements of the Vector skin.
 * WikiEditor — Provides an extendable wikitext editing interface and many feature-providing modules.

Advanced extensions
The extensions for advanced and semantic functionality, which I strongly recommend, are:
 * Dynamic Page List — A reporting tool for MediaWiki, listing category members and intersections with various formats and details.
 * Maps — Enables embedding of dynamic maps into wiki pages, geocoding of addresses and other geographical operations.
 * Validator — Provides generic parameter handling support for other extensions
 * Semantic Bundle — A pre-packaged bundle of Semantic MediaWiki related extensions — of which I have enabled:
 * Semantic Forms — Forms for adding and editing semantic data.
 * Semantic Forms Inputs — Additional input types for Semantic Forms.
 * Semantic Maps — Provides the ability to view and edit coordinate data stored with the Semantic MediaWiki extension.
 * Semantic MediaWiki — Making your wiki more accessible - for machines and humans.
 * Semantic Result Formats — Additional formats for Semantic MediaWiki inline queries.

Really useful
Some other useful extensions:
 * Contributors — to show top contributors to a page, possibly with Contribution Credits
 * Collection — Export PDFs and create books.
 * Lingo — Provides hover-over tool tips on pages from words or abbreviations defined on the Glossary page.
 * EmbedVideo — Adds a parser function embedding video from popular sources.
 * Widgets — Allows wiki administrators to add free-form widgets to the wiki by editing pages within the Widget namespace.
 * SyntaxHighlight GeSHi — displays formatted and colored source code with the.

Fighting spam
For public wikis, I also recommend:
 * Google Analytics Integration — Inserts Google Analytics script (ga.js) in to MediaWiki pages for tracking.
 * Confirm User Accounts — Gives bureaucrats the ability to confirm account requests.
 * SpamBlacklist — Regex-based anti-spam tool: MediaWiki:Spam-blacklist and MediaWiki:Spam-whitelist.
 * ConfirmEdit — Provides CAPTCHA techniques to protect against spam and password-guessing.