COUNTER (Counting Online Usage of Networked Electronic Resources) is a standard for the use of online content. She was born in 2002 at the initiative of publishers, libraries and library consortia. She gave birth to a British company nonprofit: Counter Online Metrics.
Including dissemination via the SUSHI protocol (Standardized Usage Harvesting Initiative), COUNTER statistics allow libraries to receive user data for the bunches of magazines or books for which they have subscribed to publishers. Standardized too, user data become comparable between publishers and allow libraries to have to assess their acquisition policy tools.
The standard is public, so it is possible to comply without having to pay the company to obtain a COUNTER certificate.
The debate about the use and meaning of attendance statistics are numerous.
Translated and adapted from Wikipedia.