en.wikipedia.org
en.wikipedia.org
http://en.wikipedia.org/wiki/Email_marketing
www.aweber.com
www.aweber.com
http://www.aweber.com/
www.benchmarkemail.com
www.benchmarkemail.com
http://www.benchmarkemail.com/
www.constantcontact.com
www.constantcontact.com
http://www.constantcontact.com/
www.exacttarget.com
www.exacttarget.com
http://www.exacttarget.com/
www.getresponse.com
www.getresponse.com
http://www.getresponse.com/
www.icontact.com
www.icontact.com
http://www.icontact.com/
www.verticalresponse.com
www.verticalresponse.com
http://www.verticalresponse.com/