I wonder what it takes to host a full search engine for the Internet now, if an organization wanted genuinely private search. Presumably you can buy crawls from somewhere, but does anyone sell a self-hostable general web search engine?
That I'm aware of there are only three places to get actual search index results in the US, Google, Bing (via Yahoo BOSS), and of course Blekko. You can also get index results from both Yandex (Russian) and Baidu (Chinese) but both serve them out of data centers in either Amsterdam or Asia respectively so latency is a bit longer. With modern hardware (especially 3TB drives) you can crawl a significant chunk of the In…
e.g. if I were an intel agency, I'd crawl all the jihadi sites and build a special translation/search tool for those (I'm sure they've done this). No need to crawl the rest of the pornosphere, so it could be done on one box. A commercial company could search all their industry sites locally, and then fail-through for general stuff.
I guess my main question is "how many machines are needed to do 1-3 term search on a 0.005-0.5 billion URL index" for one user with decent latency, and then how many simultaneous users could be served from that, after the index is delivered". The idea being that organizations will trust the security guarantees of a machine they own, so you could build a search service in a way that the crawl/etc. is done by one set of shared machines, bulk data streamed to everyone inside the datacenter, certain data (up to the entirety) retained by each end-user organization's query cluster, and then queries done by that cluster locally to keep search terms secret.
I assume the actual query part could fit on single machines -- you would sort of want to keep cached pages for a lot of the things you'd want to keep searches secret for, but disk is cheap.