Earlier quoted context omitted.
May I ask what you meant about "web based search implementation using elasticsearch"? Do you mean that you use ES to do indexing on the backend of your documents and make it available on the web? Or do you mean that you use ES to index documents available on the web and let people to search for them?
Sure. Your first guess is correct - I do indexing of backend documents. I fetch a steady stream of FOIA documents, close to the maximum possible each week, and PDF/OCR them. I expose a web interface to the analysts I work with, to help them gather up documents for further analysis. The second guess would probably be more interesting to most people.
I'm more interested in the second case, but I don't think ES fits due to the huge volume of data to be indexed.