Page counts down, traffic up - does this make sense?

[drall]

I have been dealing with a wierd issue with one of our oldest and most trusted sites.

Around 2 months ago it started loosing roughly 2000 pages per week out of the site: count. No loss in traffic so I shrugged it off as Google getting more accurate with its count.

2 months have now gone by and the site has lost around 40,000 pages of what was 80,000 pages indexed and continues to drop yet the traffic remains completely unchanged. Actually traffic has increased by 20% over the same time period.

Another very strange oddity is the site has 10 main hub pages 1 step down all pr 6-7 each. Every couple weeks one of these pages gets completely dropped from the index, comes back a few weeks later to only watch one of the others drop out. It is almost as if google is at random dropping out a couple of these hub pages and letting a couple others back in.

I have had our server and security guys check everything over ten times and all checks come out fine for dns/server/security/load balancing issues.

I was just wondering if anyone else is/has experienced anything like this.

How can a site loose so many pages yet its traffic increases?

How come google is dropping out powerful pages to only bring them back a couple weeks later and then drop out others?

Is it just me or does this make no sense?

[ecmedia]

Google index is dynamic and pages keep getting in and out all the time even for fairly small websites (yours is definitely huge and thus more susceptible to the churn).

I don't know about you but in general the 80/20 rule applies to most websites. 80% of the visitors come on 20% of the pages, so as long as these pages keep getting pumped up you are in pretty good shape.