This question is common in social media in my opinion. So many "experts" are working to target broad communities. However, when you have an expertise in (as some of us have) niche, diverse and smaller community engagement platforms, the social media campaign design landscape becomes very narrow and different. The basic concept of Ttwitter and Facebook no longer work to the chagrin of some that see that strategy as the "end all, be all".

What I will admit is that becoming diverse in your content and strategy lends yourself to becoming more valuable. However, ultimately, I believe you need to be both! Flexible and ambidextrous is my recommendation.