Those are some huge numbers, I’d have gone mad many links ago. I hear there can be some delay before your rank is credited for inlinks, things might improve over time. Lasting links that are proven to not be short term rented links have more pull (BTW I couldn’t find reference to your site in the source code of several inlink sources site explorer reported.)

Some backlink generation guides suggest that the number of links that can be added without looking unnatural depends highly on the age of the site. Links may be ramped up after several months of aging.

Certainly the search engines don’t give much credit for unoriginal duplicate or scraped content, might pay to hire someone to write original introductory guides for your major categories. Those "made for adsense" site packages with pre-made content don’t work like they did 5 years ago.

A site with a clearer theme might rank more easily than one attempting to cover the spectrum. I understand only authoritative sites are fed adsense ads for high paying terms like Mesothelioma artificially throwing in a lot of expensive keywords subjects might also raise a red flag. I have to wonder if 10 sites containing 400 related pages each would do better than your encyclopedia site.

The high ranked sites I have examined have relatively few low grade comment style backlinks, they seem to employ a lot of paid blogroll links from sites not necessarily related to the destination site. Many are listed in the paid yahoo directory. There may be some "balance of inlink source types" criteria used by the ranking algorithms that unnatural growth patterns may trigger. Too much fishy stuff lands one in the google supplemental index.

Discussions of the deindexing of BANS sites may mention some site qualities yours shares.

Hope my thrashing is benificial

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