The times of checking Google dances, Google PageRank updates, and Google data centers on a monthly basis are long gone. The question arises regarding how much the things have changed. The fact remains that a lot has changed but fundamentally things have actually remained the same.
John Mueller of Google has mentioned that though over the years things have changed, there is a huge doubt regarding whether it is the same algorithm it was once and he also doubts if it is used nowadays in the way it was used in the old times.
The response of John Mueller is based on the 302 redirect debate that has been going on for quite some time now.
Matt Cutts explained the factor of PageRank algorithm very clearly. He stated that it possibly changed here but the basic concept of PageRank and the way Google wants to rank the sites have remained the same. Google wants to give the top ranks to the most respected and trusted sites and PageRank was there to figure out which sites were being favored the most by the people. So, it can be said that though it has changed a lot, the end goal still remains the same.