Below I list some of the resources I found very useful for my research. 

Text mining, text processing and semantic network analysis tools 

Automap

ConText

VOSviewer

Chorus

Social network analysis tools and visualizers 


*ORA

UCINET

Gephi

Pajek

Mailing lists and Google groups

SemSocNeta Google group of industry experts and academics who want to explore the boundaries of semantic network analysis and share resources.

SOCNET: The Social Networks Listserv

Corpora: Text corpora list

Misc

Google Trends

Google Books Ngram Viewer

SociLab - LinkedIn Network Visualization and Analysis

Netvizz v1.3: a tool that extracts data from different sections of the Facebook platform.

YouTube Data Toolsa collection of simple tools for extracting data from the YouTube platform.

Digital Methods Initiativemethods and tools for repurposing online devices and platforms (such as Twitter, Facebook and Google). 

Data sources

Talk of Europe: A dataset covering all plenary debates held in the European Parliament (EP) between July 1999 and January 2014, and biographical information about the members of parliament. 

SoNIA - Social Network Image Animator

SNAP - Stanford Network Analysis Project

Twitonomy

TwiNL - provides researchers and students the opportunity to search through Dutch tweets.

Free Data Visualization Tools

Plotlydata viz, dashboards, and collaborative analysis.

Visualize Free: drag-and-drop designer for interactive visuals in HTML5.