E-mail notifications counted as spam??

I have decided to implement and e-mail notification system in my forum. Now it has only just started so I only have 17 members. My question is do I need to get express permission to include these (new members will get a checkbox on sign up) or can I just set them to be included with the normal options to opt out at the bottom of the e-mail.

Thanks

 

As your current members havn't given permission to receive any email notifications, it would be best to send them all a quick email asking their permission first before you add them.

 

Thanks I thought so. Was gonna write a mail all script anyway so I'll just not add the notifications until thats finished