Having a user's email can be extremely useful and many times necessary. When you make changes to your TOS/privacy policy, you can send them notifications. When they receive an internal private message, you can send them a notification. You can also send them updates about your service. Also, email is probably still the most powerful marketing vehicle. If you ignore it, you've just lost a very powerful ally in your path to success.
Now, how you collect this email is also extremely important. The best way to collect emails is through double-opt-in. User first requests to receive messages from you (a checkmark during the signup is sufficient) and then they confirm the subscription when they receive the email. Why is this important? It prevents people from claiming that you're a spammer. If you follow this procedure and if you keep these records (i.e. dates, IPs etc), you can defend your email when you get spam complaints from other postmasters. It is CRITICAL that you followup on these spam reports since you can easily get blacklisted on all of the email services and your emails will never be delivered. If you use email list services (like Aweber etc),they require you use double opt-in and won't allow you to add an email without it. I like these various email contact services since they deliver emails to inboxes of pretty much all of the email service providers and they fight every spam report on your behalf.
So yeah, I understand the need to have an easy signup but you should also think ahead. My suggestion is to start with no double opt-in and add it later on as your site grows and you start receiving spam complaints.
Now, how you collect this email is also extremely important. The best way to collect emails is through double-opt-in. User first requests to receive messages from you (a checkmark during the signup is sufficient) and then they confirm the subscription when they receive the email. Why is this important? It prevents people from claiming that you're a spammer. If you follow this procedure and if you keep these records (i.e. dates, IPs etc), you can defend your email when you get spam complaints from other postmasters. It is CRITICAL that you followup on these spam reports since you can easily get blacklisted on all of the email services and your emails will never be delivered. If you use email list services (like Aweber etc),they require you use double opt-in and won't allow you to add an email without it. I like these various email contact services since they deliver emails to inboxes of pretty much all of the email service providers and they fight every spam report on your behalf.
So yeah, I understand the need to have an easy signup but you should also think ahead. My suggestion is to start with no double opt-in and add it later on as your site grows and you start receiving spam complaints.