I was looking at my site using Google webmaster tools and noticed that I had duplicate title tags on some of the pages of my consulting site. Here is what I saw

You should notice that the pages like contact have additional pages with ?wpcf7=json added on.
Further investigation showed that it was probably the contact 7 form plugin causing the problem and the only course of action was to deactivate and un- install the plugin.
I also (using webmaster tools) requested that the duplicate pages be removed and edited my robots.tx file to exclude pages with ?wpcf7=json in them.
here is the new one:
——————————–
# All robots will spider the domain
User-agent: *
Disallow: /category/
Disallow: /blog/page/
User-Agent: Googlebot
Disallow: /*/?
Allow: /
—————————————
I checked that it was ok using the robots.txt checker in the Google Webmaster tools.
Hopefully in a month or so it should sort itself out as Google drops the other pages.
If you are using the contact 7 plugin you may want to check your site. I moved to the cforms plugin.- http://wordpress.org/extend/plugins/cforms/
Resources:
- http://www.google.com/webmasters/tools
- the-unusual-string-wpcf7json-will-it-hurt-my-seo


Robot.txt should work..It works at my site too..