Why SMO is needed for a website's raking?
SEO process has changed considerably (for good) in recent times, Google now values Good contents and Reputation of a business (& Website) when it comes to Search results. While it is important (most important) to create good contents, improving Brand value & reputation is a bit tough and takes considerable time.
How to use Social Media Networks to improve Reputation?
PR (Public relationship) is vital for any business (even without Google), and corporate firms use tons of TV commercials, Organized events, sponsorships and more to improve their brand value and create a reputation(& respect) for their business (& Brand) while the same is done via Social media these days, more and more of your potential customers and their friends can be tracked all the way back to their Social profile and if you increase your reputation on Social Media by creating and maintaining an impressive audience group, then WORD OF MOUTH marketing is easily possible along with reputation and free PR at no expense.
Google Loves such activities and will considerably help increase your SEO rankings, adding more to this you can also get considerable about of referral leads through Social networks.