What does Google penalize a website for?

[Webmeister]

I have read on here a lot of what we are supposed to do to optimize our ranking on Google, but how about a thread on what we are not supposed to do? I've read of a few things here and there that can decrease your positioning on Google, but I've never seen a thread devoted to this subject (if there was one I missed it). So, could you webmasters be so kind as to list the things here that Google will penalize a website for? It would be much appreciated. Thanks!

[superstar]

An anchor text penalty would not make sense since this
is something one cannot control (on external sites).
Hidden text will not make a site surviveable in a competitive
environment therefore I see no need
to use anyway.

Just my opinion on common sense :-)

[batdesign]

I think it's fairly safe to say that google penalises sites for the reasons published on their webmaster advice page. After that, everyones guessing, particularly about the recent 'index page disappearing' debacle.

Still, if anyone has any real answers about this, which we have yet to see really, I'd be interested!

If good quality sites are being dropped from the index for reasons that google hasn't published on their advice pages, what good does that do them? None...

I'd love for GG to turn up and either say yea or nay. Then we can all go to bed.

[Webmeister]

I believe that Google learned a lot from the AltaVista debacle a few years ago. AV was at the top with SEOs in the year 2000, and then they started penalizing websites for whatever they deemed "spam" and began removing them from their index. In the process, they alienated the very group of people who had put them at the top to begin with. I don't think Google will repeat that mistake again. They are smarter than that, and they will come up with more ingenious ways to stay one step ahead of us. Just when we think we have their algo mastered - it will change again.

Penalties have to be enforced, and it makes enemies. Providing an intellectual challenge to the SEOs will not only make them more friends in high places, but it will keep Google at the top where they belong.