There has been a great deal of discussion on how nonprofits can utilize Facebook and other social networks to bolster their fundraising efforts. Much of what I've read has been speculation. Anything more substantive has concluded that Facebook has relatively little impact on fundraising.
I have some more positive news to share. Sharing personal fundraising pages seems to positively affect pledge fundraising. SWEET Online Pledge Fundraising sites have an AddThis tool on every fundraiser's profile page. So participants in walkathons, bike rides, marathons, etc... can share their fundraising pages on Facebook, Stumbleupon, MySpace, or through old fashioned emails.
We've tracked the data for 3 months now and have found:
- Most of the sharing happens on Facebook, StumbleUpon, and via email.
- People that share their fundraising pages generally raise more money.
- There seems to be directly proportional relationship between sharing a profile page and how much is raised.

Conclusions
I recall from my college calculus class, that slope equals rise over run. The line in the chart above shows another $16 raised for every additional share. Does this mean that nonprofits can expect $16 every time someone shares their fundraising page? It's probably too early to tell but our data so far points in that direction.
It's important to note that not all of the sharing was done on Facebook. Most of it was but not all. Also, remember that AddThis is a very easy sharing method. It doesn't involve widgets or badges or anything that would involve a slightly deeper level of technical ability. It's also safe to conclude that the level of sharing is a good barometer on the overall fundraising activity undertaken by the event participant. If they're sharing online, they are probably also sharing offline.
In light of all the effort being spent on this subject and the lack of real data it's good to know that sharing your fundraising pages on social networks can have a positive impact on fundraising totals.