Social Media

The Register – @TheRegister

https://twitter.com/theregister
Twitter profile: Biting the hand that feeds IT. Technology and science news for world+dog. 
Follow us: Science and technology news for the world

Naked Security – @NakedSecurity

https://twitter.com/NakedSecurity
Twitter profile: Award-winning security news, opinion, advice and research from Sophos
Follow for: Security Industry news and views

Troy Hunt - @troyhunt

https://twitter.com/troyhunt
Twitter profile: Microsoft MVP for Developer Security, Pluralsight author and international speaker, you’ll usually find me talking about web security and “The Cloud”.
Follow for:  Security news and views

Davey Winder - @happygeek

https://twitter.com/happygeek
Twitter profile: Editorial Fellow Dennis Publishing, award winning journalist, animal rights supporter, vegan, collector of tattoos. File me under different
Follow for: Insight into latest security vulnerability news

LinkedIn

InfoSec Careers (Information Security)

https://www.linkedin.com/groups/1364287/profile

InfoSec Careers is dedicated to connecting Information Security and Cyber professionals interested in a new permanent career opportunity or contracting jobs with specialist recruiters and hiring managers looking for new talent. This is THE LinkedIn Group for Cyber & Information Security Jobs and all those interested in IT Security news from industry.

This group is specifically relevant for those professionals holding CISM, CISA, CREST, BS7799 / ISO27001 Lead Auditor, CISSP, GIAC, PCI QSA, CRISC, CLAS or similar certifications.

Type: Networking Group
Members: 9,120 

Jericho Forum

The Jericho Forum is an international IT security thought-leadership group dedicated to defining ways to deliver effective IT security solutions that will match the increasing business demands for secure IT operations in our open, Internet-driven, globally networked world. 
This Linkedin group only indicates interest - for actual Jericho Forum members see https://www.opengroup.org/jericho/memberCompany.htm.

Type: Professional Group
Members: 1,057
https://www.linkedin.com/groups?home=&gid=47229

SC Magazine UK (Information Security)

https://www.linkedin.com/groups/1833658/profile

This group is open to professionals working in information security and risk management and is affiliated to SC Magazine and SC branded events including conferences. The SC brand provides information and intelligence for professionals working in information and organisational security.

Its followers include FTSE 100 CISOs and CSOs who are relied upon to protect their businesses from the wide-ranging data threats that exist in the world today.

Type: Networking Group
Members: 6,334

Blog

Security Bistro

http://ddosprotectionblog.corero.com/blog/
IT network security and DDoS security news. Email security, cyber security, spear-phising

Security Bloggers Network

http://www.securitybloggersnetwork.com/security-bloggers-network-the-feed/ 
The Security Bloggers Network is the largest collection of information security focused blogs and podcasts in the world. Of the almost 300 different blogs and podcasts included, each one has requested to be included in the aggregated feed.

ConCon Blog

http://www.contextis.co.uk/resources/blog/
Contains news and detailed analysis of research projects and recently discovered security vulnerabilities from Context Information Security.