I still believe that Facebook and Google are great platforms to promote your business, but only if you are willing to pay. If your goal is Organic growth, I recommend looking at newer platforms such as Quora, Reddit, Snapchat, Medium, Instagram, Tumblr and similar. These are all established platforms that still offer some opportunities for organic reach, because although popular, they are nowhere near the saturation levels of Facebook and Google. You can also look at startups that you feel will become very successful in the future, take a small gamble perhaps and try to establish a strong presence there.
That said, ground-up marketing works because it’s work. There’s no substitute for careful attention to your website’s content and careful curation of your business’s social media presence. Paid ads can be an effective tool within a high-budget marketing strategy, but if the consumer arrives at your website and doesn’t find what they’re looking for, how is that investment working for you? It’s not. If a sponsored tweet draws them in but a discrepancy in expectation chases them away, what’s the benefit there? It’s absent. Organic marketing is a long process, but ultimately it will yield more authentic customer engagement and more accurate SEO.