i have content writers who write unique content for my website . Also i have no external links and dont think i am violating any term of google ...But why is google trimming my results . Everyday i put appx. 15 new articles and google is lowering my page count . few days ago i had 500 pages listed now it is 400 . Google almost lowering 20 pages everyday why ?
Most likely those extra pages are ending up in Google's supplemental index. Since your blog is only PR3, a lot of your pages would have low PR. You may need to work at building more links to your blog. Ideally you would regularly get links to your homepage and to individual posts.
Have you signed up for Google webmaster tools? You can submit a sitemap with them and see if there are any errors being reported like duplicate meta descriptions or something. One other thing I might do personally is post unique excerpts into the category sections to reduce the amount of duplicate content. Also, a few of the articles are pretty short. I might even combine a few of the shorter (150-200 word) ones into larger articles.
How do you protect your contents? Beware there are some sites stealing others contents and sad there are cases that the stealer get indexed first than the original site. Bookmarking, submitting updated sitemap, pinging you blog post will help index your blog and it's post.
That happens to me all the time. Its normal. Just concentrate on long term indexing. Ie.Keep a list of how many pages are index at the beginning of evert month.