Google Toolbar shows a site weight not very precisely, but it’s the only tool giving you at least some information any time you want. If you know the toolbar limitations you know at least what you see. So there are two limits in Google Toolbar:
1. Sometimes the toolbar defines weight approximately. If you open a page that is not in Google index but there is one similar in its index to this page the toolbar will show its supposed PageRank weight. This guess is useless for us because it’s not presented in any of PageRank calculations. The only way to see if the toolbar uses this guess is to type an URL in Google search field and see if it gives us the page. If not then it’s supposed.
2. The toolbar gives only the idea of a real PageRank weight! Though PageRank is linear they decided to show it in a nonlinear diagram. For the toolbar PageRank weight change from 2 to 3 takes less PageRank weight increase than from 3 to 4. This can be well illustrated in a table; the real numbers are secret. That’s why we are using random numbers to illustrate: THE TABLE.
W should hope that this illustration will show you how limited the toolbar information is.
Since now I’m going to use the term “real PageRank” to mark the authentic PageRank weight, hidden by Google and “the toolbar PageRank” to mark what is shown in Google Toolbar.