Your mental model should always be that the forum logs everything, especially since it is behind Cloudflare, which is almost certainly an NSA-backed operation. But here is some more detail. Currently there are four classes of IP logs:
- Every time your session refreshes (about every 10 minutes while you are browsing the site), your current IP is momentarily logged. This is only kept until a new such entry replaces it, except that whenever the daily database backup happens, the current value will be captured and then possibly kept for a long time.
- A tuple (time, userID, ip) is logged whenever you view a forum ad in order to produce ad stats. These are kept for only a few weeks, and are not backed up.
- Every HTTP request creates an access log, but while these contain IPs, they do not contain user IDs, and so on the whole they probably cannot be provably associated with users. These are usually deleted after a few months, and are not backed up.
- Certain actions trigger a long-term IP log. This includes posts (but not PMs), security-log entries, certain errors, and registration. Long-term logs are currently kept indefinitely.
I don't like that IPs are sometimes kept indefinitely. To prevent abuse, it would probably be sufficient to keep them for ~6 months. But keeping these logs long-term is
extremely useful for account recoveries. I've been thinking about this issue, and I think that in the future I might let users opt out of long-term IP logging if they have a public key registered in a (currently-not-existing) public-key-registration system. Though, again, even then you should model this site and all sites as keeping complete logs.
Unless I am somehow required to do so by law (though I can't see how in this case), I will not assist police who are seeking to enforce any Bitcoin ban.
If I put an image in a post in this thread, then I can get a list of the IPs of the people who have viewed the thread. Cross refer a few threads, and I can probably isolate your individual IP.
Try it and see how many IPs you get...