Vous voulez savoir comment les normes ISO 11620:2014 Indicateurs de performance des bibliothèques et ISO 2789:2013 Statistiques internationales de bibliothèques définissent les "ressources numériques" et les "visites d'un site web".

Vous trouverez ci-dessous les extraits de ces normes qui nous semblent répondre à votre question et auxquelles nous avons eu accès.

Malheureusement, la bibliothèque de l'Enssib n'est pas encore en possession de la norme ISO 2789:2013, qui semble décrire en détail le calcul des visites virtuelles. De plus, nous n'avons pas non plus pu consulter l'édition précédente de cette norme (2008). Nous avons demandé à la bibliothèque de remédier au plus vite à ces manques.
Nous vous donnons toutefois les définitions qui figurent dans la version de 2006.
 

Information and documentation - Library performance indicators : ISO 11620. 3^e éd. International organization for standardization, 2014 [norme non traduite en français]

2.10 : Digital document : information unit with a defined content, born digital, or digitized, that has been created or digitized by the library or acquired in digital form as part of the library collection.
Notes :

• This includes eBooks, electronic patents, networked audiovisual document, and other digital documents, e.g. reports, cartographic and music documents, preprints, etc. Databases and electronic serials are excluded.
• Items incorporated in databases are covered by 2.8
• A digital document can be structured into one or more files
• A digital document consists of one or more content units. before digitization, the library has to decide which content units should be searchable afterwards, e.g. articles in serials or songs on records.
• Source : ISO 23789:2013, 2.3.13

2.8 Database : collection of electronically stored descriptive records or content units (including facts, texts, pictures, and sound) with a common user interface and software for the retrieval and manipulation of the data.
Notes:

• The units or records are usually collected with a particular intent and are related to a defined topic. A data base can be issued on CD-ROM, diskette, or other direct-access method, or as a computer file accessed via dial-up methods or via the Internet.
• Licensed data bases are counted separately even if access to several licensed data base products is effected through the same interface.
• A common interface providing access to a packet of serials or digital documents, usually offered by a publisher or vendor, is also to be counted as database. Additionally, the single serials or digital documents should be counted as serials or digital documents.
• SOURCE: ISO 2789:2013, 2.3.10

2.7 : Content unit : computer-processed uniquely identifiable textual or audio-visual piece of published work that can be original or a digest of other published work.
Notes :

• This includes documents or parts of documents (e.g. articles, abstracts, content tables, images) and descriptive records.
• Adapted from COUNTER code of practice, Release 3:2008
• PDF, Postscript, HTML and other formats of the same content unit will be counted as separate items.
• Source : ISO 2789:2013, 2.3.9

L'évaluation de la consultation des ressources électroniques semble donc formalisée dans la norme COUNTER (Counting Online Usage of Networked Electronic Resources) : Counter Codes of Practice

2.56 : Virtual visit : one continuous cycle of user activities on the library website by user from outside the library's IP adress space (usually from outside the library premises), regardless of the number of pages or elements viewed.
Notes :

• A virtual visit typically starts when a user accesses the library website after visiting an external page, and ends if no activity has been recorded for a defined period of time (recommended maximum is 30 min). Another access after a longer interval initiates a new  visit.
• A virtual visitor should at least be identified by a unique cookie and/or by a unique combination of the user's IP adress and browser string (user agent). Known web spiders and harvesters should be excluded.
• Source : ISO 2789:2013, 2.3.39, modified
   

Statistiques internationales de bibliothèques : information et documentation : NF ISO 2789. AFNOR, 2006

Cette norme propose les mêmes définitions que la norme ISO 11620 :

3.2.12 : Document numérique : unité documentaire numérisée par la bibliothèque ou acquise sous forme numérique comme élément de la collection de cette bibliothèque.

3.3.29 : Visite virtuelle : recherche faite par un usager sur le site électronique de la bibliothèque depuis l'extérieur de la bibliothèque quel que soit le nombre de pages ou d'informations consultées