Online privacy
Be considerate of the privacy preferences of the users of your site.
Images from Other Sites
Don't include images from other sites on your pages - that allows the owner of the other site to track the users of your page. Instead, copy the image to your own site and point to it there. If you don't have permission to make a local copy of the image, leave it out or use a different image. See Wikipedia:web bug for more information.
Children's Privacy
Sites should not compromise people's privacy or safety, especially children.
Be sure to be in compliance with this federal law: Children's Online Privacy Protection Act of 1998 (COPPA)
Note however that COPPA applies only to commercial sites and excludes most nonprofit organizations. But it can still serve as a useful set of guidelines for congregation sites.