It was a bit unclear what I meant I think when reading it back now. With private search engine, I meant privately owned, as with google, yahoo etc. The idea was that at least all information is under the control of one entity, that can be held responsible in case something should go wrong at some point. If the information would be spread among a multitude of volunteer non profit organizations this would be harder to keep track of. Regarding https, google already offers this, it's just to add an 's' to the address, although it's still in beta.