PostOffice is an excelent massmailer,
Auto add new emailaddreses,
Auto remove emailaddresses,
Auto delete bounced emailaddresses,
Auto check for new messages,
Handle mutiple mailinglists,
Auto replay when Subscribe,
Auto replay when Unsubscribe,
Send Plain or Html messages,
Send Attachement,
Excluded list,
Import mailinglists,
Auto check for dublicates,
Auto notify when new version is avalible,
Auto add Un/Subscribe info in email

MailEnable Standard Edition provides robust SMTP and POP3 services for Windows NT/2000/XP/2003 systems. This version is free for both personal and commercial usage and does not have any time, user or mailbox restrictions. Includes POP3 Service, SMTP Service, Powerful MMC Administration Tool, Supports unlimited number of domains & emails, Supports groups/distribution lists, Autoresponder & Autoforward Mailboxes, Anti-spam control, List server ...

MailEnable Professional Edition provides robust mail services and includes functionality such as Web Mail and Web Administration with custom skins, 3rd party anti-virus scanning, enhanced anti-spam features, IMAP4, HTTPMail, POP Retrieval and Global filtering. Professional Edition provides the features and flexibility to make it the ideal mail hosting solution for small to medium sized organisations.

MailEnable Enterprise Edition is designed for organisations or ISP's dealing with high volumes of mail, requiring greater control and flexibility over mail services. Enterprise Edition incorporates web mail, web administration, remote administration, database connectivity, clustering, HTTPMail, IMAP4, Personal calendars, advanced message Filtering, inbuilt anti-spam including Bayesian Filtering and anti-virus support.

IGetMail works with your Microsoft Exchange email server to download incoming POP3 email from multiple remote servers. It supports individual and group/domain accounts. Uses dial-up networking and operates on a time/frequency schedule you define. Unlike competitors who charge per user account, IGetMail is licensed on a per-server basis for just $79 US.

5 utilities in 1 program:
"User List" with details of mailbag number, MMF file size & the number of emails waiting.
"Mailbag" identifies the owner of any mailbag and lists all e-mails in it.
"Network" lists all external postoffices, with details.
"Stranded Mail Report" finds e-mails on the postoffice that are not referenced in any mailbag.
"SMTP Addresses" creates a text file containing a list of all SMTP addresses (for remote users).