Our inbox is a great snapshot of things that were important to us at some point in time (assuming you are an email hoarder and not a inbox-to-zero proponent!). So for sometime I was obsessed with all the use-cases for parsing and understanding 10 years of my email (yes, it has been 10 years for gmail and me!)
1. Sentiment analysis of email
2. Detecting groups or networks of users (work vs. family vs. room-mates)
3. Email fatigue detection
4. Analytics for of firsts, seconds and emails with large attachments etc.
How do we parse emails?
You could check out some code I put together for parsing a thunderbird dump of my inbox here on github
What are some libraries for visualizing the analysis?
Email timeline visualization
– Similie: http://www.simile-widgets.org/timeline/
Visualizing groups and people – Immersion project at MIT
Enron email dataset (http://www.ikanow.com/blog/05/22/making-the-most-of-sentiment-scores-with-ikanow-and-r/)