need everyone's email address

We can use our exisitng email addresses to log on to the blog and make posts. That way everytime we post it will automatically show who posted what. I need everyone to send me their email addresses so I can send an invitation to everyone. Once you recieve your invitation you simply follow the link in the email to the page to log in. You then have to create a google account using your personal email address. Then log in, click accept and you will then be able to make posts onto the blog.