PS. Wikipedia could be clearer in the information supplied about IP-numbers, and the consequences of showing these.
Also, it is not a given that the present policy will be allowable in future. Under Dutch law there are severe restrictions to publishing personal data, and this includes IP-numbers. It is a fairly new law and there is as yet no legal track record; so far everybody is ignoring it, but if somebody took Wikipedia to court to force a stop to showing IP-numbers they are very likely to win. - Brya 18:12, 3 February 2010 (UTC)
I'm not certain about that, Brya - my understanding is that the WMF operates under US law and that we don't fall under the jurisdiction of the Dutch courts.
Of course US laws apply, but Dutch laws applies to Dutch citizens working on the Dutch Wikipedia and certainly also to the Dutch Chapter and any servers on Dutch soil. Other countries may have similar laws, so it is likely that from a global perspective the legal picture may be quite complicated.
Forbidding to publish IP-numbers does not have all that many consequences, as each IP-number can be assigned a random number, which can be published as long as the WMF keeps it a close secret which random number belongs with what IP-number.
Actually this may have more consequences for logged-in users. Although they are promised that a username guarantees a degree of protection, their IP-numbers are traceable: if IP-numbers were kept secret this would make a substantial difference. - Brya 05:24, 4 February 2010 (UTC)