If you use Flodesk in your business you can implement one of their beautiful opt-in forms with ease in your Showit site. They've taken the time to write an amazing article showing you exactly how to do that which you can see here:
Add a Flodesk Opt-In Form to Your Showit Site
Once you've copied the code for your form you can embed it straight into your Showit site and you're ready to start collecting emails!
Community Resources
Check out this video from Moreno Collective with more details on embedding your Flodesk form into your Showit site.