The best replacement for exchange server is imap.

The best alternatives to exchange server are rated as following:

★★★★★	imap
★★★★	smtp server
★★★★	google apps
★★★	pop3
★★★	gmail
★★★	office 365
★★	lotus notes
★★	exchange online
★★	postfix
★	mdaemon
★	hosted exchange
★	smtp
★	lotus domino
★	sendmail
	google mail
	novell groupwise
	active directory
	mail server
	pop server

Your alternative for exchange server is not listed? Suggest!

Speaking about exchange server, one probably shouldn't forget about outlook.

Other search terms related to exchange server and their ratings are:

★★★★★	outlook
★★★★★	thunderbird
★★★★	mac mail
★★★	exchange activesync
★★★	microsoft
★★★	multiple domains
★★	pop3
★★	bes
★★	outlook express
★	windows live mail
★	exchange server activesync
★	imap
★	apple mail
	outlook 2003

You have in mind a companion for exchange server and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of exchange server in all years. Click on graph for more.

exchange server

imap

smtp server