Difference between google.com and google.co.in?

Algorithm of google.com is varying from google.co.in. Google .com is a domain for International. This domain is mostly used by the USA people. Google.co.in is a domain for India. It recovers the details from India. Then all of them need an answer to the following question? How can I promote the site on google.com or google.co.in? The answer is you first collect the directories, social bookmarking sites, Articles and etc based on India or USA. Then you do more off page optimization by using these collected sites. It would be helped for promoting your target keywords.