site: operator, pages being dropped from googles index?

[wdman]

We have an ecommerce site with about 109,000 products.
45,000 are currently active, the others are currently out of stock,
and may or may not come back in stock ever.

In January a site:www.mydomain.com showed about 100,000 urls.


Today we are showing less than 40,000, and appear to be dropping about
10,000 a week.


I have 4 sitemaps in google webmaster tools with ALL product links and
some category pages plus the homepage.


I have a decent robots.txt file and have recently (just yesterday)
requested a removal request for a subdomain that we are integrating
into the product pages(reviews section)


I am concerned that I have induced a penalty.


The site is as clean as I can get it and I actively monitor my stats
etc, including disallowing known bad spam bots so that they do not try
and steal my content, to post on their site.


Any advise or thoughts are appreciated.


PM me for the site url.

[sniperhiga]

What is domain name of your store? I should take a look.