Hi friends i have in doubt while creating backlink to my website. Should i use this url: http://www.breakthesecurity.com or i should use this url: http://breakthesecurity.com are they same?or any difference in page rank calculation?
They are the same, but while these plain and ordinary links are counted as backlinks (use the shorter one without the www), they’re not given near as much weight as if they were to be anchor text links. Take advantage of every opportunity you have to create anchor text links rather than than just a standard link. In your Anchor text you then place your target keywords. Then, the more links you build up using your target keyword phrases in anchor text links, the higher up in search engines your website is going to rank when someone searches for that keyword. Not alway possible depending on the site and if it lets you use anchor text for a URL... But definitely use it if possible because google uses those kewords as describtion for your link
You can find out what you need to know here: https://www.google.com/support/webmasters/bin/answer.py?answer=44231&hl=en
having ur site accessible with http and without will mean like having 2 sites..so ur pr 4 site will mean two pr 2 sites ....so u may want to corrrect this usingg rel=canonical tag...if u have already done that then i think with www looks more cool so builld links for www