I haven't written much about my immigration status, because frankly, there hasn't been much change over the years. The process moves at a glacial pace, and two or three biometrics appointments aside, I am still where I was in 2007.
While you wait for your case to be processed, there's mostly nothing to do but to wait and freak out, because the authority does not provide any real answers if you asked them about the status. Here is an example of a written response I received when I asked about the status of my application:
The status of this service request is:
A visa number is not available at this time. XM0265
Make of it what you want. Apparently it means that maybe my case has already been adjudicated (i.e. decided) and I am now only waiting for the visa quota to become available. Maybe. I could not get further than that with the "customer service" rep on the phone.
Each year, a certain number of immigrant visas (a.k.a. Green Cards) is made available for the immigration authority to hand to people like me. There are rules governing how many visas each of the many immigration categories will get. I won't bore you with the different categories and what they all mean, suffice it to say, that they hand out visas on the first come, first served basis. Your place in line is determined by the date on which you first initiated the process, which is called the priority date. Once a month, the immigration folks publish a Visa Bulletin where they list the status of each category, so you can see how much longer you have to wait.
This month, my priority date has become current, which means that maybe my case will be taken off the shelf and reviewed by someone. Or not. Apparently there are no guarantees of that happening just because your priority date is up.
From here, I may get an appointment with the friendly authority, where they will interview me to help them decide whether to let me stay. Legend has it that sometimes you just get your green card in the mail. That would be nice.
As luck would have it, my German passport is going to expire in November this year. So I figured, let's get a leg up on that and start the process of getting a new one. The Consulate is right here in San Francisco, and appointments are readily available. They also have a checklist of all the things I will need to get this started. A photo is one of them, sounds easy enough, even though they say that they have to return 90 percent of all applications because the photos aren't good enough. Being German, they provided a multi-page booklet with all the requirements and good and bad examples. Armed with it, I think I should be able to get the photo right.
Now the next requirement is not for the faint of heart. Turns out that if your passport lists a German residence address (as mine does), in order to have a consulate process my application I need a paper from the Berlin authorities saying I don't live there anymore. Which I think I got at some point. Or not. It was almost seven years ago, and I don't remember. Thankfully, the City of Berlin has a very comprehensive web presence, and I was able to download and print the un-registration application, fill it in, and physically mail it to the friendly Bürgeramt Steglitz in Berlin. Hopefully they will promptly stamp it and send it back, so I can get my new passport.
In the meantime, I am going to keep my appointment at the consulate to make sure that I am not missing anything else, because it would suck if the US Gummint came to me to stamp that long-awaited visa in my passport, and my passport was expired!
 "Biometrics" is a fancy name for having your fingerprints and your mugshot taken annually. What drastic changes in my hands and face they expect to catch, I don't know. Once taken, both pieces of data are swallowed by the authority never to be seen again, judging by the fact that I always have to provide new mugshot pictures to renew my Employment Authorization document (EAD). When the newest one arrived, it had "Not available" written in the field where my thumb print would go.
 I like the doublespeak of calling me a customer, when I have to use their "services" and follow their procedure under the risk of deportation. While I understand that I am here by choice, and immigration is a privilege, not a right and blah-di-blah, it's much easier to say this from the comfort of your country of citizenship. When you've lived in a foreign country for six years like I have, paid the taxes, and built a life here with real human connections, a home, and a career, you get tired of the constant vague threat of losing all of this because some bureaucrat misplaced your paperwork or decided to deny your petition.