what would get a site banned?

other than the usual "black hat" stuff, I mean...

[stapel]

I know that there are deliberately-abusive things that a site can do that can quickly result in the site's being banned from Google. But what other things might cause a site to be banned?

I ask because I have a specific site in mind. It's not mine nor connected to mine, so my question is just a matter of intellectual curiosity.

Site S is an academic and educational site, with minimal ads (but they are Google ads). A couple of months ago, I noticed, when trying to use Google to search for something on the site, that Site S is no longer listed. (And no, the Google-bot has not been banned in their robots.txt file.)

Site S has been around for ages, and Google used to list its pages. There are still tens of thousands of legitimate educational, often "big name" university, sites listed in Google that link to Site S, but Site S itself is not listed. And I can't for the life of me figure out what Site S might have done to cause this.

I would like to learn what sorts of things/content/activities/scripts/whatever can cause the accidental (?) banning of otherwise apparently worthwhile sites.

Thank you.

Eliz.

[tedster]

A great place to start:

Dropped Site Checklist [webmasterworld.com]

[annej]

It might not be connected to anything they did at all. Perhaps a 302 hijacking or a change in the Google algo meant to catch spammers. Sometimes innocent sites get caught in the that net.

[stapel]

Tedster: Thank you for the link. But I couldn't find anything in the referenced "checklist" thread that would appear to apply to the site I have in mind (unless having a consistent page style really is a problem, and I can't see how it would be). The site is completely gone from Google and, despite tens of thousands of valid in-links, it has not been relisted in the months since having been banned.

annej: Thank you for your suggestion. I have no idea if somebody has done a 302 hijack of the site, but even if the site had been hijacked, wouldn't that just mean that it would rank lower? I hadn't thought that it would be removed entirely...? It strikes me as doubtful that this site could have done something to get itself banned long-term "by accident". Nothing apparent changed on the site between, say, six months ago and now.

Having a non-commercial academic site myself, I was hoping for something a bit more specific (and comforting) than "it's just one of those things." Oh, well....

Thank you.

Eliz.

[annej]

It would just be ranked really low. Did you dig down to the bottom of the supplementals?

[reseller]

Hi Folks

stapel has graciously stickied me the url of the site in question.

site:www.thesite.com and site:thesite.com returned:
Sorry, no information is available for the URL bla..bla..bla

So the site for sure is not in the index.

Its a Mathematics & Algebra related site with AdSense spots. Have also noticed that several related sites linkback to the site in question.

Have checked some pages for duplicate contents, and couldn't find any.

Here is some food for the thought!

When run a query on Google with quotes "www.thesite.com", I got about 33,500 results!

A query www.thesite.com (without quotes) returned:
Sorry, no information is available for the URL www.thesite.com

[g1smd]

Since Matt Cutts allows URLs on his blog, and WebmasterWorld does not allow URLs in posts here, I think you should post the URL over there and ask the same question...