The article lists down the softwares used at different layers in the LinkedIn platform layered architecture.

Presentation Layer

• Dust.js (Client-side templating JS engine)
• Backbone.js (Client-side MVC JS framework)
• JQuery 
• YUI Library (UI libraries started by Yahoo engineers)
• Google V8 Engine (Used as server side JS templating engine)
• Node.js (Used in mobile app)
• HTML5 (Used in mobile app)

Business Layer

• Java (Applications such as Profile)
• Grails (Applications such as a Recruiter app)
• JRuby (Applications such as a Skills app)
• Spring (Component Model)
• Scala

Middleware

• Apache Kafka (Distributed entreprise-level messaging system)

Data Layer

• Oracle (RDBMS as primary data store used for writes)
• Espresso (NoSQL data store emerging as primary data store and envisioned to replace Oracle)
• Voldemart (NoSQL data store serving many Read-only pages)
• Zoie (Lucene) 
• Bobo (Lucene)
• MySQL
• Databus (Change data capture system)
• Hadoop (Map-Reduce)

Cross-cutting concerns

• Apache Helix (Clustering management)