Social media plays a dominant role in Gen Y's personal and professional lives. Between Facebook, Twitter, Instagram, Foursquare and Pinterest (and I'm sure I left out a few), it's sometimes hard to understand how young adults have time for anything else. They're using these platforms to show off everything from their work accomplishments to what they ate for lunch to their most flattering, "Look at this cool thing I did" photos. Some are even using the word "hashtag" in conversation.

So why don't all credit unions have a social media strategy in place? (By the way, having a Facebook page with 25 fans doesn't count.) For starters, many credit unions can't afford to hire a full-time social media expert.

According to Dan Greenfield, president of social media consulting firm LISTEN Interactive in Atlanta, some create a traditional Facebook profile and try to friend followers instead of setting up a fan page–a big no-no for businesses on the site. Others assign social media duties to a young intern without realizing that his or her lack of solid business and marketing knowledge can be detrimental. One key to successful social media marketing is to not just post, but to make sure each post plays a role in your long-term business goals, Greenfield said.