I have been maintaining several mailing lists on my server for a number of years now, and being marked as a spammer has sometimes been a problem, despite my use of quite conservative configuration options. When I was using Nebula as my ISP, I needed to change to use their mail server as a relay, as the DSL-style IP-address seemed to get flagged for spam every now and then. I got rid of that problem with the relay, to be replaced by Nebula's relay server being on SORBS blacklist or somesuch every now and then because of, apparently, some of their customers sent mail which caused the relay to pop into the blacklist, and having to explain that to my users.
But nothing has been worse than Gmail. The sorry amount of email flowing through the handful of mailing lists is just too much for ol' Google, so now I need to learn new tricks. I can no longer use the ISPs relay, as there is no such thing (lazy frenchmen), so I need to handle this all by my poor self. If the giant would explain how I could remedy the situation, all would be better, but now I have to guess.
I'm a programmer, not a system administrator, and all of this stuff with SPF and DKIM/DK and bulk mailing guidelines (what? it is a mailing list!) is making me sick!
To try to get rid of this shit for the forseeable future I am going to try to implement DKIM and SPF for the outgoing mail, and put the mailing lists under mailman to get all the nice unsubscribe headers and list signatures and other nice features, which should also indicate to the f-ing Google that these are dogdamn mailing lists and not bulk e-mails!
I found these nice resources