Here are four easy things you can do to test your message:
1. Do split tests on emails that you send out - with different messages in the subject lines of messages to different people, to see what is most likely to persuade people to open the emails.
2. Use the click analytics on these emails to find out which subjects people want to find out more about. This is obviously has similarities to 1. but you can test a wider range of subjects.
3. Web page comparisons - as with emails test how people respond to different messages. An excellent example of how this was done is provided by the Obama Presidential campaign.
4. Use advertising metrics. Facebook and Google adwords make it very easy to test different versions of adverts that are shown to the same audience. You can rotate primary messages, wording, pictures etc. and measure how your audiences react.
Corporates routinely use market research to inform their campaigns. And they routinely use message testing tactically for individual email campaigns. But it's surprising how few are using online testing to test their overall corporate narratives, or even competitive creative treatments on different marketing campaigns.