Sign up using the link at the top
Go to your settings by clicking on your name in the upper right. This lets you decide which notifications you want to receive. I don't know as this actually works, so no matter what you set, I can guarantee you will get notifications.
Choose a nickname if you wish - just edit your profile. I would like to balance basic privacy (i.e. you may not want your full name out there) with a sense of actual community (i.e. pick a name that insiders will be able to recognize).
Be nice. Any posts that are rude, offensive, combative, angry will just get deleted. Don't say anything here you wouldn't say in a public meeting in person. And yes, we all have opinions about the state of the world. There are other places to discuss that. And, of course, no spam.