Some quick answers.
Infraction points stay active for 30 days.
If you accumulate 30 points within 30 days, you are "banned" for 7 days
If you accumulate 60 points within 30 days, you are "banned" for 1 month
If you accumulate 90 points within 30 days, you are banned permanently
"Banned" means you get a messages stating "You've been banned" (or something similar) when you log in. You cannot use any of the system resources like PMs, you cannot post, you cannot read messages and so-on.
Users who attempt to circumvent the banned status will be banned permanently and their IP addresses blocked.
The system has, indeed, been in place for years, but we very rarely use it, because there are few problems. I think I've used it once since I implemented it.
No one but you can see your own infractions except for mods and admins (I'm the only admin). I don't recall the details, but I think there's no page to see unless you get an infraction. I could be wrong about that - it's been a while.
In the 10+ years that Newf Net has existed, 16 people have been banned. It's just not something that we like to do. Still, we do get complaints that people break the rules and that I/we don't do anything about it, so this should help in that regard.
For a description of the rules, check the "Rules" link at the top of every page. I'll try and update that Rules document to reflect the point system when I get a chance.