http://en.wikipedia.org/wiki/URL_normalization Basically the canonical URL tag lets Google know if different URL's are the same. It's important to prevent duplicate content issues.
Sometimes when dealing with canonical issues, 301 redirect is used because its the best possible solution to it......
Hi Canonical issue is a major problem for Google point of view. in this issue a web site open with "www" and also without "www". And Google treat this domain as two different domain, and if your are a SEO Experts then you must know that this called a spam domain. So please avoid to using canonical issue.
Just go through the matcutts video for canonical link. It will be very simple for you. search mattcuts - canonical link in google.
canoical link can be defined best by the example for ex if a site named abc.com if it opens with http:// abc . com if it opens with http:// abc . com index.htm if it opens with http:// abc . com and other combination then it means that the site has canonical issue from seo point of view it should open with only one URL and if another combination is applied then it should redirect to only one URL
i don't understand canoical link? pl any one give detail answer. because my website was last 15 days no keyword search through google. but all daily links are indexed in google. what reason? pl understand my questions? how to update my site daily links to google or other search engines? my site was one year old. but still no big traffic? just 300 visitors daily. i am waiting for anyone reply this questions. thanks