I'm new to all this and am putting together a learning project. I've decided on finding similarities between users in a data set such as http://en.wikipedia.org/wiki/Enron_Corpus. After doing a bit of research, I also came across Dataset for Named Entity Recognition on Informal Text. So I'm not short of data or a goal, I need to understand high-level techniques to get there.
One valuable comment noted that this question appears too broad. What I was hoping to find with this question was the breadth of techniques I should focus research on, not answers that are immediately implementable. Please consider vague answers as entirely appropriate!!
Expanding on the goal, I am hoping to discover which authors might have affinity toward each other, or conversely do not care much for each other. So I will definitely need to start with Named Entity Recognition and build a means to organize the documents against those entities. Beyond that, I am not so sure.
What high level concepts should I be looking at? Thanks!