I have an accessibility function that allows users to change the size of my site. The easiest and most accessible way for me to apply it was in link form. So someone can click the link "A" which had a href of "?size=14" and all the text would change to 14px.
As this doesn't change the contents of the page Google lowers my PR, and I am indexed badly.
I have recently changed it to a form method, which looks horrible and is less accessible.
The thing is, some programming forums I have demonstrated what I have done by adding a link with a querystring variable in my message. This would still work, as form and querysting methods both work.
But G will still see this link, and maybe keep my PR low. This could cause a problem.
I could, if I was malicious, link to all my competitors with an unused variable in the querystring, "www.example.com?lower_pr=yes". Google would find this, but see there is no difference in the HTML and see it as a duplicate page.
Isn't it about time G fixed this problem, as I have talked about it before.