You get to see everything in the site with out becoming a member (with the exception of attachments).
However, being a member allows you to be able to post comments on other posts, participate in the BREEDERS section where you can share your birds' photos and information about yourself with other fanciers, get in discussions with other fanciers who are members of the site, etc.
There are other benefits to being a member also, like being able to communicate through private messages with other members who may or may not be willing to publicly share their contact information.
When you log in to the site you are also able to quickly distinguish which section has new posts by the topic icons and if you like by checking the "Notify me when a reply is posted" box get an email from the system when a message is posted on your favorite areas.
Since the system keeps track of your logged in visits, when you log in you can click on the "View New Posts" button (top left corner area) and it will bring up a list of tpic that had activity since your last visit.