Powerset feels they can challenge Google. They say they can give better search results and they will be able to attract a lot of users.
Many others have said the same thing but were not able to do it. Possibly someone will do it in the future. It may or may not be Powerset. It is also possible that Google will be able to meet any challenge they may face.
Powerset says they are the next-generation search engine. They call it Natural Language Search. This is what is generally called semantic search and Powerset isn't the only player in the game.
With semantic search, searchers conduct their searches by using everyday language. This will often mean sentences in the form of questions. That could be their biggest problem because so many people search by only typing two or three keywords. They are going to need to change the way people search.
Powerset says they are up to the challenge and will do it on a gradual basis. They say their search results will be more relevant that those from Google because of these natural language searches and that will attract users.
One problem facing Powerset and others is the fact that Google isn't just standing still. They have also been working on something like this and are probably prepared to do what they need to do to face a challenge.
Powerset wants to allow people to see what they are all about. They don't want a flood of people all at once so they are inviting people in based upon their ability to handle them.
You can sign up for the alpha if you want to try what Powerset feels is the next generation search engine. Here is the link
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