Yes, social networking is more useful for site marketing and create an business promotion.

Post interesting news surly you will get more traffic compare to others

yes, social networks helps alot, to generate traffic for site.

yea there is no doubt about it that because today marketing is possible through social sites example online selling and buying products.

Social media is really necessary thing to maintain online reputation of a company.
Through social media you can generate leads,maintain your brand online,can make good brand reputation with customer engagement.