I use CampusGroups to compose and distribute a weekly newsletter for a student group. Normally, the email is shown in full through a program like Microsoft Outlook. On 11/21/09, however, the email only contained a link that said "Click here to open this email (31kB)". I didn't change any settings that I am aware of. Why might this have happened?
We have put a new setting in place to speed up email delivery, which replaces emails by a link when the body of the message exceeds 300,000 characters.
The size limit used to be 30,000 characters but has been raised to 300,000 (as of 11/30/2009). The link should only appear for very large newsletters (300kb and up). You can view the size of your message when you preview an email in CampusGroups, right before sending it.