Official Google answer: Should a "Sale Page" be in a robots.txt file to avoid duplicate content?

Should a "Sale Page" be in a robots.txt file to avoid duplicate content? (these products are also on the site separately).

Google's Matt Cutts answers:

Summary of the answer:

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Question	Views
What impact does "page bloat" have on Google rankings?	935
If Google crawls 1,000 pages/day, Googlebot crawling many dupe content pages may slow down indexing of a large site. In that scenario, do you recommend blocking dupes using robots.txt or is using Meta Robots noindex,nofollow a better alternative?	875
There seems to be little impact on human visitors where in the site's structure a given page is, so: Is it better to keep key content pages close to root, or have them deep within a topical funnel-structure, e.g. food/fast-food/burgers/hamburgers.php	917
What are your opinions on optimizing an e-commerce website where the main pages/products may not necessarily be rich content?	855
A question to non-intended duplicate content: If an online shop can be reached through several TLDs (like .de, .at, .ch) and the only difference is the currency (and necessarily the checkout process) does Google consider this duplicate content?	760
Do dates in the URL of blogs or websites help determine freshness of the content or is it largely ignored?	830
Will DiggBar create duplicate content issues?	743
Is it a good thing to put 'nofollow' in links to a disclaimer, privacy statement and other pages like that with the internal PageRank in mind?	892
Are product description pages on an e-commerce site termed as duplicate content, if the same product description appears on other sites?	913
We still have old content in the index. We block them via robots.txt, use 404 and delete via Webmaster Tools, but Google still keeps it. What can we do to quickly delete content from the index?	809

Question

Views

What impact does "page bloat" have on Google rankings?

935

If Google crawls 1,000 pages/day, Googlebot crawling many dupe content pages may slow down indexing of a large site. In that scenario, do you recommend blocking dupes using robots.txt or is using Meta Robots noindex,nofollow a better alternative?

875

There seems to be little impact on human visitors where in the site's structure a given page is, so: Is it better to keep key content pages close to root, or have them deep within a topical funnel-structure, e.g. food/fast-food/burgers/hamburgers.php

917

What are your opinions on optimizing an e-commerce website where the main pages/products may not necessarily be rich content?

855

A question to non-intended duplicate content: If an online shop can be reached through several TLDs (like .de, .at, .ch) and the only difference is the currency (and necessarily the checkout process) does Google consider this duplicate content?

760