Thanks to the Internet, there have never been more marketing sub-specialities than there are right now. The only thing that's certain is that tomorrow there will be even more.
Many agencies focus on just one of these sub-specialities, whether it be social media marketing, content marketing, search engine marketing, or any of a long list of others. They'll try to convince you that they have the solution for your marketing challenges. They don't.
Truly effective marketing is a custom-tailored combination of tactics, coordinated through a deep and thorough strategy, and driven by a laser focus on your brand. The only real solution to your marketing challenges is a one-of-kind program that only makes sense for you.
Your company is unique. Your marketing should be equally unique.