No need to explain much on Google in general way.Because,you all know what it is. You might have not get some techie related things on Google,here this techieteach tutorial will teach you.
Usually Google let you to access any of Google’s product with a Gmail account. If you haven’t get any Gmail account,it’s recommended to create one.
You can use Google search engine without signing in. Simple trick behind the Google search engine is, when you and your colleagues search same things, you both will not end up with same results.
Google usually track their users search results and it keep a copy of the users frequently visited websites and frequently searched things. Whatever you search on Google. Google will search those things first in your frequently visited websites,then it will display other sites which has the searched content in it.
This all will happen only when you login to Gmail account. If you not login with Gmail account also,Google will track your data through your IP Address. Based on the search make on the IP Address will track and then it will provide data from them.