linktrip
18 - The magic number?Search engine optimisation experts who have studied page rank vary in their calculations, but there is a magic number in the range of 18 - 20 that they come up with. What is this magic number?
Well, it is the number of themed links from a page ranked page that you need to get the same page rank on your site. So get 20 links from PR4 mortgage pages and your own mortgage site should also get a PR4, for example.
There are loads of "ifs" and "buts"! The page should have no more than 50 external links and should be closely themed. More external links increase the number, less decreases it.
Does this hold water?Does this work? Well, looking at the page rank calculation in a very basic way and you receive 85% of a share of the page rank of the pages that point to you. So if 1 PR4 page points at you and that only has your external link, then you get 85% of that PR4 (about PR3.4). If that page has 2 external links, then that share is halved.
Apply that to a link exchange directorySo look at the typical link directory page. Say 40 external links on the page would mean that on a PR4 page, the links value is worth 1/40th of 3.4. But most links directory pages are lucky to have even a PR1!
Looking at the maths again, if you accept 100 exchanges with links directories with page rank 1 pages and each has 40 outbound links, then you receive back 85% of 1/40th of a page rank of 1, 100 times. Work that out and it seems quite good - it would indicate a low Page Rank of 2.
Getting a Page Rank of 2Going back to the magic number 18, the same experts also state that about 105 links are need to get a page rank of 1 above the donating site. So 105 links from PR1 sites should give you a PR2 - agreeing with the formula calculation above
Surely double that number for a PR4? Well, actually no. The experts calculate that again the magic number goes up by a factor of around 5 to increase the ranking to the next stage, so around 500 - 600 good PR1 links give a PR3 and 2,000 to 3,000 PR1 links give a PR4.
What does a link exchange need?So, what does this mean for the average link builder? Well, trying to find a good number of links from directories is difficult enough, especially when the pages must be themed and must be at least PR1. When many link directory pages are less than PR1, the maths really gives us huge figures and makes frightening reading.
But, the result is that to get a decent page rank through link exchanges would require literally thousands of link swaps through highly themed sites with at least a page rank of 1 with no more than 40 external links per page. Difficult enough to find a couple that fit this description. But 3,000 of them?
I think not. That is why I just delete every link exchange request without looking at them.