Distribution lists (lists of email addresses) in Outlook 2003 come with a size limit. This is based on the size of the individual contacts not strictly on the number of contacts. However, the upper limit will generally be around 125 to 130 contacts (and may be lower if you're storing additional information about individual contacts).
For larger lists, mailing lists maintained directly on the ISU mail server have several advantages over application distribution lists.
For more details, refer to Outlook Distribution List Size Limits.Posted by dcoates at November 09, 2005 08:59 AM