Your own website vs. Facebook?
A member of the “Community Empowerment through New Media and Innovative Journalism,” session at Independent Sector (moderated by Ben Binswanger of the Case Foundation), just asked the above question.
I’m going to answer that question here. The problem with this question is that it implies an either/or choice. In my opinion, the answer is all of the above with a third piece the questioner left out. This is NOT about your organization setting up a nice website vs. setting up a nice Facebook page! It’s about not just having a website, but also ensuring your champions have the tools they need to take action wherever they want, including Facebook. It’s about having little satellite presences in those places, IF YOUR SUPPORTERS HANG OUT THERE.
Here’s what I mean:
ONE: A nonprofit needs a basic website that has key information on why anyone should care about you, why your work matters, and how to engage with you.
TWO: In addition, you need to provide portable elements on your website so people who find you online can spread the word about you in other places online. Don’t have a “what’s news” page, have a “what’s news” RSS feed. Don’t just have a donate button. Enable people to fundraise for your cause anywhere they want. What will happen then is those champions will start spreading the word all over the place, creating the Flipped Funnel phenomenon.
THIRD: Build toward a few hubs around the Internet where your audience tends to congregate. If you take step #2 AND regularly explore online where people are talking about your issue, you’ll know where to go.

When I saw the title I assumed you were going to pick one or the other but you didn’t. Which I agree with. People should keep in mind that there are hundreds of social networking sites out there and you should take the time to put up as many as possible and link everyone of them to your site.
If you want to be found online then you need to scream, “HERE I AM!!” You do that by being in as many places as possible.