As an alumni chapter leader, we'd always like to know what's on the minds of our alumni. What kind of events they'd like to see, how they would like to be engaged with the University's mission and so on. Since it isn't possible to speak with everyone, surveys and polls can be useful tools to get this information.
If you use Facebook Group for your club's social media channel then you may know that you don't have some of the bells and whistles that Facebook's Pages functionality has like allowing you to create a call to action button. Never fear! You can make your email sign up form available on your page.