I'm still of the opinion that if you're going to go for competing with Google, Bing, Blekko or even Duckduckgo you're going to have to beat them on quality of results. Reason being that most people are going to go to the site that best answers the query they are entering. I'm not sure privacy, API or even adding social context is going to provide a huge boost.

However, sometimes people need different ways to search. That's why I built unscatter.com as it provides web and social results in a chronological order. It's more useful for topics you're trying to keep up with rather than new searches. For example there's a lot of technologies (and my favorite NFL team) I like to keep up on what's new about. I use this search at least every 3 or 4 days to keep caught up. http://unsctr.me/OyY534

If you're going to go after the search market I think you need to come up with a new way at looking at it entirely. I've reached the point where I'm probably better off building my own crawler to continue further, the risk of using free API's is a bit much to build a business on. For example I had to drop Twitter a few weeks ago because their policy changes.

I don't think just changing policies around search is enough, duckduckgo already did it.