Before writing this post I did to do some tests and experiments to confirm my theory.. I wanted to share my Google SERP Ranking Theory and open this up for discussion to see what you all thought.. So here we go: Previously (6mo - 1 year ago) when you picked up a new link to your website for a certain keyword SERP rankings would increase a bunch and then gradually fall backwards as Google calculates the PageRank of the link.. SERPS would typically go up and then fall back if the link was weak. Now when someone new links to my site (recently a PR8 site linked to me) the rankings for that keyword actually fall a little bit until Google can calculate the new Pagerank and then you slowly move up in the rankings.. Things have reversed from the way the use to, instead of getting an automatic boost with a new link, it now seems that you get an automatic fall back until Google has time to calculate the link.. I guess this change was made in order to keep people from short term boosting their rankings with links that are from low pagerank/authoritative sites.. I have seen this trend with a lot of different links (high PR and low PR).
But what is the reason of fall in rank? At least it should remain same and slowly go up. or it should slowly comedown and than move up as you get new link.