7.5.3 Burden of proof
7.5.3.3 Non-traditional publications
The internet is also used to exchange and publish information in ways which did not exist before, for example via Usenet discussion groups, blogs, email archives of mailing lists or wiki pages. Documents obtained from such sources also constitute prior art, but establishing their publication date may be more involved, and their reliability may vary.
The content of a transmitted email cannot be considered to be public simply because it could have been intercepted (T 2/09).
Computer-generated timestamps (usually seen, for example, on blogs, Usenet or the version history available from wiki pages) can be considered reliable publication dates. While such dates could have been generated by an imprecise computer clock, this should be weighed up against the fact that many internet services rely on accurate timing and will often stop functioning if time and date are incorrect. If there is no evidence to the contrary, the frequently used "last modified" date can be treated as the publication date.