People are more likely to submit information online, if they can do it easily – in virtually no time. Don’t suppress that benefit.
When collecting data, ask only for the minimum initially . Unless you’ve got a strong incentive to make your recipients provide more. But in that case, keep in mind that some subscribers may only be in it for the reward, rather than for the relationship.
The only information you really need to start email marketing is an email address. Ask only those questions that you need to begin your relationship.
If you want more information, just offer the recipient a chance to update his profile in every email you send him.