Funny duplicates observation

[HitProf]

A client of mine has put up a page that turned out to be a duplicate. The text had actually been provided by on one of his suppliers. He didn't like it, so changed a few words and put his version online. I was totally unaware of this until I tried to find the page in Google for a specific keyword and couldn't find it. With only 83 results I decided to investigate and changed the filter to 0. To my big surprise the page turned up #3, right below it's (almost) duplicate. This is how I detected it was a duplicate :)

I was even more surprised when I searched for the site's most important but also most difficult keyword: this exact same page showed up at about 25, which was a lot better then I expected for any page from this site for this keyword in this stage of development. This keyword was one of the words in which the text was diffent from the original.

Anyway - I asked the client to rewrite the page completely, I want the other keyword as well :)

Bottom line: apparently Google doesn't penalize whole pages if they are 80-90 % duplicates but only the duplicate parts. Ather parts can rank quite well!

[ciml]

No one has managed to explain to me what the duplicate penalty is.

100% duplicates are merged, including backlinks and PR, so no penalty there. Near duplicates are offen filtered; only the first appears unless you append &filter=0 to the search results URL or click "repeat the search with the omitted results included", but I wouldn't see that as a penalty either.

HitProf, I'd say that what you experienced is the usual case.

[HitProf]

ciml,

Perhaps 'penalty' is not the right word but let's skip that bit.

It's about the page showing up for certain keywords but not for others, so it's regarded as duplicate for one search but not for another.

[cabbie]

This has always been the case as far as I Know.Many spam sites have automatically generated pages all identical except for some choice keywords.The duplicate filter stops more than 1 or 2 results showing for each keyword but every keyword will show in google.