Semantic search would allow for greater precision in the definition because you can specify in a way you cannot do with keyword search. I do think Tauchain or something like it is necessary for decentralization of the web. I do not think we should be required to rely on big companies to do our computation if we can rely on more fundamental peer to peer infrastructure.
So like how at one point in time we required FTP servers until Bittorent? The same can be true with something like Tauchain for search.
RE: How Tauchain and the Exocortex can give anyone a conscience and make anyone more law abiding