Huge Disparity in "site:" Results Between Data Centers

[pdivi]

When I run a "site:domain.com" search on the different data centers, I see two very distinct grouping of results:
1) 200-250 pages found
2) 8000-8500 pages found

I haven't seen much fluctuation in these numbers over the past month.

What does this kind of chasm between data centers usually mean? Are some centers applying a filter? Can you offer any guidance on which centers deserve more attention than others?

[tedster]

Are you only talking about data center results seen when you poll them directly by IP address? Or do you also mean google.com results that are served from different IP addresses?

[pdivi]

tedster, I am using an online tool that polls multiple datacenters and returns the results in iframes....or the equivalent of your first scenario.

[tedster]

Then it seems clear that many of the URLs are being filtered before your domain's spidering is made available live on google.com. The most common reason for this kind of filtering seems to be link juice (PageRank) but if you do an analysis of your own case, you may find that some other characteristic is involved.

[anallawalla]

For over a month I see an extra 2M pages for our site: if I check from home compared to the office (not logged in). Parent company is also the country's biggest ISP, so a colleague using that ISP from home gets the same count as at work.

The only difference I can see is that my home ISP is not powered by the employer's ISP arm. Yes, I typed ISP, not IP. Weird.