Hi!
In Google Webmaster tools I see a lot of crawling error (404 errors) entries like that:
http://www.mysite.com/?page_id=9236&cid=Mjg%3D
?page_id=9236&cid=NTU%3D
?page_id=9236&cid=MjU%3D
?page_id=9236&cid=MjA%3D
?page_id=9236&cid=Mjc%3D
What is that?