Small businesses are actually more able to scale and measure themselves on social media. Every minor thing on social media is extremley valuable. For every follow, like, share etc. it is hugley valuable and measurable for smaller companies as other users have choosen to do that specifically from experience with the company etc. where as with larger companies some people may just like, follow, retweet etc. because everyone else is doing it.
With smaller marketing budgets, social media is a great way to increase awareness and improve search results. Social media plays a part in the higher ranking in Google. The more popular you become on social media channels it will help you appear in Google searches without you having to spend loads of money.
Facebook is brilliant to use as a current newsletter for the company. The bigger the audience you grow on there through news, interaction, good content, imagery etc. more followers will choose to share your page as there is genuine interest and good content being displayed. You can use facebook to let the world know your news and what the company is getting up to.
The followers and likes your receive are all referred because the user wanted to. With genuine followers you have a more than likely chance that your content will get shared, commented on and liked on the social media channels you publish it on.
Doing what your best at works. Being a smaller business means you may not have time to constantly be concentrating on updating every social media channel. By working out what channel works best for you and what your more confident with using you can stick to increasing your followers/engagement on those channels and then eventually move to another.
Social media is brilliant for businesses, especially smaller businesses as it is a free way of reaching to the world and as so many users are online you can build an audience of hundreds, thousands, and more.