First you don't think about growth as traffic. Traffic to your site is simply one action, just as phone calls, visits to a store and social participation. They all bring potential value if planned right.
For a small business I'd suggest social is more actionable than at any big company. This is because your customers are already invested in you, pick you for some particular value you provide and as such are ideal to communicate with and eventually spread your name.
Those two elements make up the core goals of social: interacting with customers to inform them, learn from them and participating to strengthen their relationship to your business while simultaneously giving them a reason to share your business either directly [through a link] or indirectly [by performing an action].
How exactly you do this depends greatly on your business and, since you've provided no details on that I can only suggest vague details but basically you want to start with building a following which means providing content that's intriguing enough to want to follow you for and respond to whatever comes in. This is also critical as small businesses often treat social as a broadcast medium posting what amounts to ads and rarely checking for replies, questions, thoughts... People expect to hear from you and that means you have to be willing to devote resources to win, or even play.
So if you can tell us more about your business we can respond back with more thoughts...