What is the right perspective for applications to talk from? [duplicate]

1. How much duplicate content is acceptable?
2. What is the most common fix for duplicate content?
3. Which of these is one possible solution for dealing with the duplicate content issue?

How much duplicate content is acceptable?

How Much Duplicate Content is Acceptable? According to Matt Cutts, 25% to 30% of the web consists of duplicate content. According to him, Google doesn't consider duplicate content as spam, and it doesn't lead your site to be penalized unless it is intended to manipulate the search results.

What is the most common fix for duplicate content?

What is the most common fix for duplicate content? In many cases, the best way to fix duplicate content is implementing 301 redirects from the non-preferred versions of URLs to the preferred versions.

Which of these is one possible solution for dealing with the duplicate content issue?

The Solution: NoIndex

Rather than use a canonical tag to point back to the master page, the better solution here is to add a noindex meta tag to each page to keep them out of the search engines' index altogether. Generally, these pages tend to be orphans, not having any direct links to them from inside the site.