superclown2 - 10:08 pm on May 17, 2012 (gmt 0)
But there are differences between adding -amazon.comm and -anydomain.com.
For my site this means, adding -amazon.com -> prepenguin results,
adding anydomain.com -> better but still penguin results
It seems like if the added domain suppresses something like a niche penalty/filter.
Like if keyword matches amazon _-> #1 amazon #2-#9 brands etc.
if amazon is filtered -> prepenguin
I have seen strong indications in the past that Google run more than one database, and that the ranking rules are different for each one. If my theories are correct then which database comes into play depends on the search terms submitted. Therefore, the main money search terms are treated in a different way to more minor, or long tail, terms. Main search terms for red widgets are treated in a different way to those for green widgets. Therefore, adding some garbage to a common search term will mean that the query will be handled by a different algo altogether, and thus give completely different results, than the case would have been had the original term been entered.
This is the cause of a great deal of confusion amongst webmasters who expect more straightforward results to queries and this is, I believe, whilst not necessarily the only reason for this procedure, a very useful one to Google for keeping the algo opaque.
In analysing results it is necessary to think outside the box a little and not assume that a simple logical sequence will take place. It most certainly won't.