Aimee - 3:05 am on Mar 15, 2006 (gmt 0)

Thanks Tedster,

Here are some things you can check: Do both the no-www and the with-www versions of the old site redirect with a 301?

Yes, both with 301 redirect to new site.

Is it really a 301 and not a 302?

Yes.

Do all the urls from the old site redirect or just the home page?

Sure, all urls redirect.

Do you use a custom error page for either domain?

Yes.

If so does that page return a 404 header -- or is it a 200?

404

Does the no-www version of the old site 301 redirect to the with-www version?

Yes, to new site with www version.

If yes, on all pages or just the home page?

All pages.

Do you link to the home page by using the domain name only, or do you use index.htm, home.asp or some other page name?

Insite link to home.htm, but outsite(back link) link to domain name.

Do you do any click-path tracking in a query string, rather than with a cookie or webbug?

Yes.

Are you using session ids in the url query string?

Yes, we use session ids.

Are you doing any content negotiation and serving different content at the same url to different user?

No.
But we do google adwords and add a track code like?=google_adwords in the URL.

Any of these things can cause excessive duplicate content issues and cause pages to vanish, over time.

The session ids? well, if may. or the links to home page?
and the google sitemap doesn't value?