What's their bias? I couldn't find it.

This is from their about us page:

AboveTopSecret.com is the Internet's largest and most popular discussion board community dedicated to the intelligent exchange of ideas and debate on a wide range of "alternative topics" such as conspiracies, UFO's, paranormal, secret societies, political scandals, new world order, terrorism, and dozens of related topics with an impressive demographic mix of members.

The simple yet effective motto of our membership is "deny ignorance", which signifies an effort to apply the principals of critical thought and peer review to the provocative topics covered within.

The Motto: "Deny Ignorance"
More than a slogan and deeper than a mission statement, our members have embraced the motto of "Deny Ignorance" as our reson detre, demanding everyone who posts to aspire to a higher standard of participation. These simple two words have galvanized a broad membership base that spans the spectrum from highly speculative conspiracy writers to staunch skeptics. The result is a unique collaboration of diverse individuals rallying under this simple statement to learn from each other, discover new truths, and imagine new ideas that expand minds.

This motto has life. It has purpose. It demands ATS members to think.

It is a state of mind.

It is a sense of purpose.

It is a statement against the paradigm.

It is a rage against the mindless status-quo.

The idea of "deny ignorance" isn't a goal that ATS hopes to accomplish. Instead, it's a challenge. A call to all those who come here to aspire to a higher state of awareness through informed discussion and debate.

Deny ignorance is what we do.

It's how we think. It's how we talk. It's how we listen.

Ignorance is the social disease of history that has clouded our minds and dulled our brains. Is the evil that men do, the reason history repeats, and the cause of intolerance.

We deny it. it's not welcome here. Within these boundaries, it has no strength.

Here, ignorance is denied.

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"No one believes more firmly than Comrade Napoleon that all animals are equal. He would be only too happy to let you make your decisions for yourselves. But sometimes you might make the wrong decisions, comrades, and then where should we be?"
- George Orwell Animal Farm