This site is open to all descendants of John and Annie Raven (and their spouses). If you're not sure if that includes you or not, a good rule of thumb would be: if you have ancestors that were Ravens from Maine then you probably qualify. Go ahead and register and I'll let you know one way or another!
If you do not belong to the extended Raven family of Maine, you will not be granted permission to access the site. If you DO belong, but it's not readily obvious to me, you need to explain your connection when you fill out the registration form or you will not be authorized.
Most of the content here can only be seen if you are logged in to the site. To get a username/password, you must first register (see the link in the upper-right corner). Once you've been approved (give it a day or so), you'll be able to log in.
If you find that the username that you want has been taken (which should be pretty common with so many people having the same last names!), then I'd recommend using your email address for your username. Easy to remember and it'll be unique.