I'm trying to plan an email campaign and was wondering what process I should go through in order to identify how frequently our subscribers want to hear from us.
Hi Kris, you can do some pretty clever stuff with your preference center and custom fields here. For example, you could create a custom field, 'How often do you want to hear from us?' (with values like, 'Every week', 'Every month'...), add it to your preference center, then prompt your subscribers to fill in this detail via your next email campaign. Here's some more info on preference centers.
Alternately, you could try linking to an 'How often do you want to hear from us?' poll, created in Wufoo or similar :) You can then use Wufoo to populate the custom fields of your subscribers with the results if you please. All the best!