• http://neo4j.com/ - graph database
• https://gephi.org/ - for visualising graphs. Also possible to export to a website.
• QGIS http://www.qgis.org/en/site/ + POSTGIS http://postgis.net/
• What's a good tool "for dummies"?
• No panacea. Problems that people want to solve with data are too varied.
• Intermediaries
• http://data-journalism-tools.silk.co/
• http://openrefine.org/
• https://d3js.org/ - Visualisation
• R - data analysis and predictive models
• Ptyhon
• matplotlib
• pandas
• http://python-xy.github.io/
• JSON schema
• Web inspector in your browser

Linkedin groups are very good for conversations about tools like these.
Stack overflow
Slack groups e.g. https://neo4j-users.slack.com/
IRC

Things people have built with open source tools:

• https://women-in-film.silk.co/
• http://www.meptwitter.eu/

Not open source:

• https://www.import.io/
• https://zapier.com/ for feeding output of one tool into another tool

JavaScript license information