Our mail server will reject messages with more that 100 recipients with a "554 Too many recipients" error message.
This limit is actually very high for good email practice. Some providers will reject messages with 50 or even 30 recipients.
In addition, the long list of recipients will make it difficult to have your email delivered to the intended inboxes. In some cases, you may get a bounce back because the list has pushed the size of the mail headers past the accepted limits of a provider. For instance AOL may respond:
reason: 552 REQUESTED MAIL ACTION ABORTED: HEADERS EXCEED 32K BYTES OR RECORD TOO LONG
In other cases, the long recipient list will result in the message being treated as spam and either accepted and dropped without being delivered or else delivered to the recipient's junk mail folder instead of their inbox.
Generally when there is that many recipients for a message there is a likelihood that some of the recipients will not want the email and report it as spam. Our acceptable use policy ( http://support.digitalwest.net/KB/a135/digital-west-networks-inc-acceptable-use-policy-for-email.aspx) requires that you remove such addresses immediately from your mailing list. However, these spam complaints typically come back with the email address masked to protect this sort of thing from being used to validate real email from bad ones in dictionary style spamming. If you are simply using an long list of email addresses from a standard mail client instead of mailer which adds a per address unique identifier to the mail header or message, you will not be able to comply.
Another consideration when using a long recipient list is that you are exposing all the email addresses to everyone on the list. That may be taken as a huge violation of privacy by those receiving such emails.
Article ID: 149, Created On: 1/4/2008, Modified: 9/23/2010