Small business owner & author. Founder of http://giftcardproject.com. Ardent about helping the homeless. Big fan of marketing, writing, sports, poetry, politics & hip-hop.
It depends on the type of startup and the users its products are aimed at reaching. Twitter is best for influencing the influencers whereas Instagram would best target a younger audience. These days Facebook is, on the other hands, increasingly used by an older audience (35-55).