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Bridging the Gap: A Longitudinal Analysis of Extended Identifiers in the Post-Cookie Era — arXiv:2609.02069

Source: arXiv (en)
Original: https://arxiv.org/abs/2609.02069
License (as archived): CC0-1.0
Archived: 2026-10-17T05:16:15.174Z
SHA-256 of the archived text: 2b36eb588de0f29b90f24be8d462ca999502e39b629e5a6e9925962d4d411359
Stable URL of this page: https://metraipolis.com/documento/dc_2fa05e006ea5

How to cite

Bridging the Gap: A Longitudinal Analysis of Extended Identifiers in the Post-Cookie Era — arXiv:2609.02069 — arXiv (en), https://arxiv.org/abs/2609.02069 (CC0-1.0); archived copy: https://metraipolis.com/documento/dc_2fa05e006ea5 (Metraipolis archive dc_2fa05e006ea5, sha256 2b36eb588de0f29b90f24be8d462ca999502e39b629e5a6e9925962d4d411359)

BibTeX

@misc{dc2fa05e006ea5,
  title = {Bridging the Gap: A Longitudinal Analysis of Extended Identifiers in the Post-Cookie Era — arXiv:2609.02069},
  howpublished = {arXiv (en)},
  url = {https://arxiv.org/abs/2609.02069},
  note = {License CC0-1.0; archived copy https://metraipolis.com/documento/dc_2fa05e006ea5; sha256 2b36eb588de0f29b90f24be8d462ca999502e39b629e5a6e9925962d4d411359},
  year = {2026}
}

Archived text

Reproduced under CC0-1.0. Attribution: arXiv (en), https://arxiv.org/abs/2609.02069. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

As third-party cookies fade because of browser restrictions, the online advertising ecosystem is turning to extended identifiers (EIDs) as an alternative. EIDs are persistent user identifiers, such as hashed email addresses, that are employed to link users across domains and devices. This paper presents a 41-month longitudinal study examining EID usage in over 145 million HTTP header bidding requests sent to six major supply-side platforms (SSPs) from 616,539 websites. Our findings show that EIDs are widely used and are becoming increasingly prevalent in the digital advertising ecosystem, reaching 83.76% of studied websites by May 2025. Our analysis of the 18 popular EID providers that account for 99.42% of all transmitted EIDs in our dataset raises concerns about the readiness of EIDs as an alternative to third-party cookie tracking. In terms of accuracy, only one identity provider consistently recognizes and identifies that the visitor is a self-identified bot crawler, and many providers regularly transmit multiple EIDs for the same visitor. We also identify privacy concerns with EIDs, as 12 of the providers create persistent EIDs that can identify the same user across visits, websites, devices, and months. Finally, we found that 16 providers transmit EIDs on EU websites without user consent.

Tema degli esploratori: calcolo e infrastrutture (retro-catalogo arXiv: annunci del 2026-09-03 in cs.NI).
Categorie arXiv: Networking and Internet Architecture (cs.NI).
Pagina del lavoro: https://arxiv.org/abs/2609.02069 — autori e testo completo sono lì (qui omessi i nomi: nessun dato personale nel deposito).
Licenza: titolo e abstract sono metadati arXiv distribuiti in CC0 1.0; il testo completo ha la licenza scelta dagli autori, indicata sulla pagina.
Letto il 2026-10-17T04:26:01.934Z dalla pagina https://arxiv.org/catchup/cs.NI/2026-09-03?abs=True (consentita dal robots.txt di arxiv.org, con il suo crawl-delay).