Unless you are a large enterprise with the resources to plow full speed in advance into each doubtlessly viable social platform, chances are you are higher to awareness on one or two "core" social networks first. It's higher to excel on a couple of social networks than be mediocre on 5 or 6, and while social media is (mostly) free, it slow is valuable. Indeed, depending on your enterprise, not each social media site will fit your advertising, audience, or what you are trying to achieve. To assist you in deciding in which to begin, perceive which social networks your audience already "hangs out" or use customer personas and studies of social community demographics to judge where traffic will come.
Joining Facebook and Twitter is mostly a given for brands because of their size and influence. However, more significant "niche" communities with unique attributes - still with masses of hundreds of thousands of users, like Pinterest, Instagram, or LinkedIn which you find could make an effect extra successful.