Share 'Book Blog Tours—What are they?'

Can anyone help me figuring out the whole book blog tour thing? In my research to query book blogger reviews, I found Innovative Book Tours Online (http://innovativeonlinebooktours.com/) and I'm wondering if the services they offer are the norm, because I have no idea. Are there other "companies" like this one? Do they do the same thing? Paid? Unpaid? If you're on a promo budget, can an author pu…