I would like to know about the sub domains and there benifits for us. Do Sub Domains really help us out for boosting our keywords?

Sub-domains are considered like stand alone ones and valued accordingly. In other words, example.com is a completely different domain than SEO.example.com .

Sub-directories are located after the domain name (ie example.com/experts ) and are considered part of the main domain. Those certainly seem to have an SEO advantage when logically named using a keyword or two. An example could be example.com/SEOexperts .

Sub Domains can help you to understand that "How you can boost traffic on your website and get your keywords ranked accordingly".

commented: you actually haven't said anything in all that -2

Sub domain can help your to boost traffic to your website..write some quality contents about your niche keyword and
Create some subdomain
publish some article on add add hyerlink directed to your website...