WhatIs defines Above The Fold as “the portion of a web page that is visible in a browser window when the page first loads”. Wikipedia defines it as "the portion of a webpage that are visible without scrolling". This concept is important if your nonprofit is in the process of redesigning its website and/or if you are responsible for creating landing pages for any specific call to action, such as Requests for Donations, Invitations to Join as Members, and Requests for Volunteers, among others.
According to Jakob Nielsen, 80% of your constituents will not read below the fold, so it's important to make sure that if you are requiring your constitutents to take any specific action (Donate, Volunteer, Purchase, Become a Member, etc), to include this information above the fold to increase your conversion rates.
Some argue that it's not as important to include your call to action above the fold. As more and more people access the internet through their mobile devices, what is above or below the fold is relative to the device type one uses. In addition, it has become a habit for people to scroll. So if you follow that rationale, people will scroll to the bottom of your page. While both these arguments are true, it is also true that people have shorter attention spans so it is still important to consider including your important messages and calls to action above the fold while they are still engaged in your page.
Following is the home page we designed for Eco-Farm. Their calls to action are above the fold.