I thought it was about time I got involved in this debate.
First of all thankyou all for taking an interest in the rankings!
The main difference between the cricketweb rankings and the ICC rankings is that the ICC considers games played over a period ranging from 2-3 years, for some reason revolving around August as a cut off point. The cricketweb rankings consider results from the most recent meetings between all teams at home, away and neutrally. In some cases, this can be as much as 4-5 years, but often fits within the same 2-3 year window. However what this does mean is that we don't just exclude certain matchups simply due to the way the itineraries are drawn up.
In the last 3 years, it is likely that several combinations of teams have played each other on at least two separate occasions, yet other combinations won't have played each other at all, and this makes the system unfair. For example, a side which has played Bangladesh and Zimbabwe more than it has played Australia would be buoyed by that and a team that has played Australia more than those two would be punished. Why should this be so?
That is why we chose to do the rankings the way we do.
Unfortunately I won't have access to the rankings database until the weekend but I am always happy and willing to answer any questions people have about the rankings, and certainly don't mind a bit of healthy discussion of them!