When an internet document is cited against an application or patent, the same facts are to be established as for any other piece of evidence, including standard paper publications (see G-IV, 1). This evaluation is made according to the principle of "free evaluation of evidence" (see T 482/89, and T 750/94). That means that each piece of evidence is given an appropriate weight according to its probative value, which is evaluated in view of the particular circumstances of each case. The standard for assessing these circumstances is the balance of probabilities. According to this standard, it is not sufficient that the alleged fact (e.g. the publication date) is merely probable; the examining division must be convinced that it is correct. It does mean, however, that proof beyond reasonable doubt ("up to the hilt") of the alleged fact is not required.
The publication dates of internet disclosures submitted by a party to opposition proceedings are assessed according to the same principles as are applied in examination proceedings, i.e. they should be assessed in view of the specific circumstances of the case. In particular, the timing of the submission as well as the interests of the party submitting the disclosure should also be taken into account.
In many cases, internet disclosures contain an explicit publication date which is generally considered reliable. Such dates are accepted at face value, and the burden of proof will be on the applicant to show otherwise. Circumstantial evidence may be required to establish or confirm the publication date (see G-IV, 7.5.4). If the examiner comes to the conclusion that - on the balance of probabilities - it has been established that a particular document was available to the public at a particular date, this date is used as publication date for the purpose of examination.