Hi friends, I am about to build link for my site. It is very low in search engines. I want to ask one question when i put url in my mail, is adding www. is must or i can go on with only http://mydomain . com? would be grateful for your kind reply
It is bad because some might see it as duplicate content and if you get 50 backlinks from one site with www and other 50 with www, it won't be the same. Learn how to redirect to WWW.
You want to prefer either www or non-www. Otherwise this leads to cannonical issue. Better you can undergo 301 re-direct from non-www to www version
Both versions can get you backlinks.... It depends on you which version you want to highlight. You need to set one domain as preferred domain in Google Webmaster Tool, to avoid duplicate content issue (but this will split your backlinks, because some websites will link back to www version and some to non-www version) OR you can redirect your one domain to the preferred domain