Every single page needs to have a unique title to gather more clicks.
Length of a title is ideally to be within 8-9 words. It should be good to read so that users find the idea of the body interesting and clicks on the title. Success of SEO marketing services depends a lot on the title, and so, the main keyword must be present in it along with one or two others, akin to the original in meaning. Modification aka variation indicates reaching out to wider set of audiences.
Uniqueness of title tag causes search engines to crawl each page separately, which is why alteration of main keyword is essential. But the title shouldn’t be keyword staffed. Such titles aren’t gripping and go against principles of internet advertising.
Title tag is always written in <head> section of your HTML document. The complete format will look like
<html>
<head>
<title>Something here</title>
</head>
<body>
Content of the page
</body>
</html>
The content of Page title tags are displayed in search results 70 characters is maximum range.
How to Indentify?
Method 1: Review Google SERPs using Google search syntax: site: www.domain.com “page title” 
Method 2: Using Xenu link sleuth crawled data >> sorting by title >> find groups of titles with the same title
Method 3: Using Page Comparison Tool (http://tools.seobook.com/general/website-comparison/)
Using Web Developer Tool: https://addons.mozilla.org/en-US/firefox/addon/web-developer/
Steps: Information >> View Link Information >> Identify Links of the website >> use page comparison Tool >> CSV Export >> Sorting By title
Method 4: Using Google Web Master Tool >> Diagnostics >> HTML Suggestions >> Duplicate Title
Solution:
Case I: Title duplication cause due to following:
- Pagination
- Case sensitive URL
- Canonicalization
Proper implementation of canonical tag should be done in above cases, which would help in solving duplication issues and consolidate pages. Therefore, it is suggested to use the main page URL as canonical tag.
In case of pagination: For the pages www.example.com/about-us.html and www.example.com/about-us-1.html, canonical tags <link rel=”canonical” href=”http://www.example.com/about-us.html”/> should be used for both the pages.
In case of case sensitive URL: For the pages www.example.com/about-us.html and www.example.com/About-us.html, canonical tags <link rel=”canonical” href=”http://www.example.com/about-us.html”/> should be used for both the page.
In case of canonicalization: For the pages www.example.com and www.example/index.html, canonical tags <link rel=”canonical” href=”http://www.example.com”/> should be used for both the page.
Case II: Title duplication case for two different pages.
The title of a page is of key importance in SEO. It is suggested to develop unique, optimized and relevant titles for the pages and incorporate the same in the pages. Title should not exceed 65 characters. Title tag should be kept unique to make a better impact on search engine ranking.
Case III: Short Page Title or Missing Title.
The title of a page is of key importance in SEO. It is suggested to develop unique, optimized and relevant titles for the pages and incorporate the same in the pages. Title should not exceed 65 characters. Title tag should be kept unique to make a better impact on search engine ranking.
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