SurveyMonkey.com - Powerful tool for creating web surveys. Online survey software made easy!
It cannot be stressed enough on how important it is to get feedback from your customers/mailing list on what they exactly want from you. I found surveymonkey.com to be a very hands on site that lets you do surveys and collect these vital information.
To members of Cashflow Club I am giving away a FREE voucher for a 1-on-1 consultation on setting up the survey for your particular market.