For those that have done this, are there any specific legal requirements that you have to follow? For example, I would imagine that you'd have to get the permission from the charity to use their name and likeness on your site. Do you have to keep charity funds in a separate account or file any additional paperwork with the IRS? Does anybody actually audit this stuff?
In addition, does is it better to donate off of your net or gross revenue? What's a reasonable percentage to donate to make it effective (I imagine that's also dictated by your profit margins)?