Whats the difference in terms of SEO, PR, or SERP or why all want a domain?Anyone please share some proffesional concepts.
SEO wise I'm not sure there is actually a difference?? As far as I know, there is no gain for having a .com over a .net in terms of your rankings.. Isn't "www" technically a form of subdomain anyway?
As far as I know the subdomain inherits a minimal trust from the main domain, so the start may be a little bit easier. I doupt that there would be any difference concerning PR and rankings. I think most people want an own domain. If you have one, you may like launching subdomains, under successful domain label.