search by knowledge not by Google
Wolfram Alpha is a search engine, but it's not pretending to be Google, and it isn't trying to do "search". It's actually doing something more subtle: it's doing semantic search. It depends on data (trusted) and not keywords (crawl the web and index)
Google uses tweaked versions of its original "lots of people link to this page" algorithm. Wolfram Alpha is closer to Wikipedia and is looking to distinguish between Ford, the car, and ford, the method of getting across a river as input and therefore deliver results that are of value.
Impact on Digital Footprints - Wolfram Alpha doesn't care as it is looking for facts and how it can be compared. If this is future search, will privacy go away?
Excellent video from Ted Talks on what they are developing