(3)
There is an outstanding post by Dr. Pete on SEOmoz named Duplicate Content in a Post-Panda World.
The article isn't really Panda specific, but it talks about duplicate content issues in 2011, which is the year of Panda.
Here is the outline, but make sure to check out the article:
I. What Is Duplicate Content?
II. Why Do Duplicates Matter?
(1) The Supplemental Index
(2) The Crawl "Budget"
(3) The Indexation "Cap"
(4) The Penalty Debate
(5) The Panda Update
III. Three Kinds of Duplicates
(1) True Duplicates
(2) Near Duplicates
(3) Cross-domain Duplicates
IV. Tools for Fixing Duplicates
(1) 404 (Not Found)
(2) 301 Redirect
(3) Robots.txt
(4) Meta Robots
(5) Rel=Canonical
(6) Google URL Removal
(7) Google Parameter Blocking
(8) Bing URL Removal
(9) Bing Parameter Blocking
(10) Rel=Prev & Rel=Next
(11) Syndication-Source
(12) Internal Linking
(13) Don't Do Anything
V. Examples of Duplicate Content
(1) "www" vs. Non-www
(2) Staging Servers
(3) Trailing Slashes ("/")
(4) Secure (https) Pages
(5) Home-page Duplicates
(6) Session IDs
(7) Affiliate Tracking
(8) Duplicate Paths
(9) Functional Parameters
(10) International Duplicates
(11) Search Sorts
(12) Search Filters
(13) Search Pagination
(14) Product Variations
(15) Geo-keyword Variations
(16) Other "Thin" Content
(17) Syndicated Content
(18) Scraped Content
(19) Cross-ccTLD Duplicates
VI. Which URL Is Canonical?
VII. Tools for Diagnosing Duplicates
(1) Google Webmaster Tools
(2) Google's Site: Command
(3) SEOmoz Campaign Manager
(4) Your Own Brain
Phew!
Forum discussion at Sphinn.
Image credit: Bannykh Alexey Vladimirovich / ShutterStock.
