I just wanted to drop a quick follow-up and give everyone a list of email clients and spam filters our new Campaign Preview service runs a test of your creative against. You can also get more detail on the service here.
Email programs your email will be tested in:
AOL 9
AOL Web
Comcast
Earthlink
Gmail
Lotus Notes
Mail.com
MSN Hotmail
Outlook 2003
Outlook 2007
Outlook Express 6
Outlook XP
Thunderbird
Windows Live Hotmail
Windows Mail
Yahoo! Classic
Spam Filters tested in:
McAfee SpamKiller
Norton AntiSpam
Outlook 2003
BrightMail
MessageLabs
Postini
Spam Assassin
IronPort
Yahoo! Mail