Here is a list of Web 2.0 resources about Ada:

News & Blogs

• reddit.com — Ada [RSS], social news website on which users can post links to content on the web.
• Stack Overflow — Ada questions
• Ada Gems, programming tips and articles about specific language features.
• Ada Planet, news aggregator.
• Ada Programming blog [RSS], by Martin Krischik and other authors.
• Java 2 Ada [RSS]

Social Networks

• @AdaProgrammers at Twitter
• Linked In — Ada developers group (free register needed)
• Gitter chat room

General Info

• Ada Resource Association
• Awesome Ada, a curated list of awesome resources related to the Ada and SPARK programming language.
• SlideShare, presentations about Ada programming, Ada 95, Ada 2005, Ada 2012 tag pages.
• Open Hub, a directory of Open Source projects. Its main features are source code analysis of public repositories and public reviews of projects
• Ada@Krischik, Ada homepage of Martin Krischik
• WikiCFP — Calls For Papers on Ada [RSS]
• AdaCore channel on youtube.com, Ada related videos.

Wikimedia projects

• Wikipedia articles (Ada category):
  • Ada
  • Jean Ichbiah
  • Beaujolais effect
  • ISO 8652
  • Ada Semantic Interface Specification
  • ...
• Wiktionary entries:
  • ACATS
  • Ada
  • ASIS
• Wikisource documents:
  • Steelman language requirements
  • Stoneman requirements
• Wikibooks tutorials:
  • Programación en Ada, in Spanish
  • Programmation Ada, in French
  • Ada, in Italian
• Wikiquote:
  • Programming languages — Ada
• Wikiversity:
  • Ada course

Source code

• Examples Ada Programming wikibook
• Rosetta Code — Ada Category, programming examples in multiple languages

Projects

• AdaCL
• The Ada 95 Booch Components
• The GNU Ada Compiler
• ASIS
• GLADE
• Florist
• GNAT — GCC Wiki
• RTEMSAda
• AVR-Ada - Ada compiler for Atmel microcontrollers (Arduinos)
• Ada Bare Bones - Tutorial to write a small Multiboot kernel written in Ada