Online giving for nonprofits is growing, but remember, it still makes up only a small portion of total giving.
Traditional fundraising — direct mail, events, major gifts — still generates about 90% of total giving. It's important to allocate the appropriate percentage of resources toward traditional channels rather than focusing exclusively on online fundraising, which seems cheap and easy.
Online fundraising is important, and should be integrated with your direct mail program, but it should not be overemphasized in light of its contribution to total giving.
Check out Mart Pitam's blog "The Danger of Seeking 100% Online Giving" for more information.