People usually consider the two as search engine sites but they obviously have some slight differences with each other. The Wolfram is known to be an answer engine wherein you can type in your question and choose from different answers that are available on the website. When you type in a few keywords at Google, you will be redirected to various websites that are supposed to give you the answer.
These two can both be used in order to gather the details and the information that you need on the internet but the way that they will provide you with answers may be different from each other. Google is also more popular than Wolfram but this does not mean that this Answer engine does not have fans from different places.