What is the best way to get data on who is litigating, who is being sued, and over what patent? For only 5000 lawsuits it would be relatively easy to understand the scope of the problem.
It would be nice to just read in the court filings, which are a public record, and produce data extracts to explain the world. Unfortunately the PACER system -- officially a public agency -- charges you by the page for those public documents.
Once you've got them, they're free for you to share, but sharing projects threaten the revenues of the system and the publishers (Westlaw and Lexis) that prosper from the lack of public access to public data. Those publishers and PACER have worked hard to block and shut down and even bring unrelated federal prosecutions against people who organize free systems.
One of the reasons Aaron Swartz was a major target of federal prosecutors even though his nominal accusers didn't want charges brought is that he was active in promoting free access to federal court documents. [0]
Companies like Lex Machina [1] work with the officially supported publishers to offer analysis of patent lawsuit filings and patent office documents (also officially but not really public) to answer questions like yours for very wealthy clients.
