Technorati Rank is a number assigned to your blog based on the number of blogs linking to you. When you create a blog and claim it at Technorati it is assigned a rank. See the picture below :
Then I created another test blog and put a link in it to the first blog created above. I then looked at the revised rank of the first blog and saw that it had jumped nearly 35%. See picture below :
Such huge jumps are seen only initially. As the ranking number decreases addition of a link may decrease the number only by a few hundreds.
The link count is calculated by looking at all links from the past 6 months. That means rank will change daily based upon your blog's activity from 180 days ago up to today. As older links fall off link count and new links are added, link count may increase, decrease, or stay the same. This means that even if links are displayed in the search results those acquired before 6 months are not taken into account when calculating the rank. Hence anyone attempting to increase his/her rank with Link Exchange experiments will have to repeat them every six months or whenever the rank starts sliding.
This means that after the first six months to prevent your rank from sliding you will have to acquire links at the same rate as you will be losing your180 days old links.
NOTE : 1. Only links in posts and sidebar and blog rolls are counted. Links in comments and backlinks are not counted here.
2. If you change the URL of your blog you do not take along your ranking unless you do a 301 redirect.
Replace BLOG_URL with the link of your blog without the initial "http://" This will give you a graph of number of links acquired daily. If you see your Technorati Rank dropping you will see a chart with a lot of initial links and decreasing links later on in the time scale. That is then the time to indulge in some vigorous link-building exercises.