If Website is 2-3 years old and we change the URL from xyz dot com to abc dot com? Does SEO or traffic will go down?
I have combined 3 existing  websites into one new website www.xyz.com and i redirect the old one to a new one  .I have copied some content from the existing site.so,do i need to add canonical tag for each page in the new web? or is there any duplicate content issue?