Fairly new, small companies rarely have the kind of advertising funds/ resources available to well established, large companies. This means they have to find and make use of whatever means of promoting their products/ services are available at low or no cost at all.
In traditional forms of advertising, one of the most powerful promotional tools is 'word-of-mouth' recommendation. Thanks to modern Internet technology, online businesses, too, can use this exceptional tool to promote their services/ products.
The main platform through which it is made possible for companies to reach world-wide PC, laptop, tablet and smart phone users and 'spread the word' is social media. From Facebook and Twitter to a whole host of other social media networks, this platform allows effective branding of and spreading news about a company quickly, easily and at incredibly low cost.
Creating relevant pages, regularly updating quality content and linking this content back to the company's main Website takes little time, incurs next to no expenses and will - even if it reaches only a fraction of the millions of users around the world - bring in substantial and potentially continually growing numbers of prospective customers/ clients.
In short, social media requires very little in terms of resources while providing an advertising platform of almost unlimited potential, making it a tool no small business should fail to use.