WordPress blog - 30% goes supplemental

[lee_sufc]

I have a site with a blog installed at www.example.com/blog

I have noticed that lately, a lot of my newer pages aren't being indexed. When I did a site:www.example.com/blog search on Google, it seems that 30% of the pages are now supplemental?

Why could this be? I put the following in my robots txt to prevent any potential duplicate content:

Disallow: /blog/wp-
Disallow: /blog/feed/
Disallow: /blog/trackback/

is there anything that could be causing this?!?

[edited by: tedster at 5:46 pm (utc) on June 5, 2007]
[edit reason] switch to example.com - it can never be owned [/edit]

[tedster]

Sometimes a URL shows as Supplemental in a site: search, but stills shows up in the actual SERP without the Supplemental tag. How does your actual traffic to those URLs look?