The robots.txt disallow:/ will not make your hide your URL’s the Google search engine’s. The biggest thing is that if you use a disallow and noindex tag on the same page both will have a conflict. A disallow tag makes the content and meta details hidden from the eyes of Google search engine. The noindex if used in that page will not be taken by the search engine as the Google search engine not use the Get function to fetch the meta tags. So the best thing is to use a noindex tag in robots.txt if you do not want search engines to index your hidden page. The greatest example of the conflict is diggbar which is a noindex as well as disallowed one. http://www.google.com/search?hl=en&q=eriuqs+spires+healthy+recreation+site%3Adigg.com&btnG=Search&cts=1240047550677
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