Update README.md

README.md

@@ -66,7 +66,9 @@ companion paper](https://arxiv.org/abs/2502.12103)
 
 This dataset represents a 100M anonymised sample of 30 days of Criteo
 live data retrieved from third-party cookie traffic on Chrome. Each line corresponds to one impression (a banner)
-that was displayed to a user. For each impression, we are providing:
+that was displayed to a user. It is partionned by day (`day_int`) to facilitate exploration, model seeding and train/validation/test split.
+
+For each impression, we are providing:
 
 - campaign x publisher x (user x day) granularity with respective ids, to match Chrome Privacy Sandbox scenarios and both
 display and user-level privacy.
@@ -108,7 +110,6 @@ display and user-level privacy.
 -   We include a display order from 1 to K for display on the same day
     for the same user.
 
-CriteoPrivateAd is split into 30 parquets (one per day from 1 to 30) in day_int={i} directory.
 The displays-per-user histograms can be deduced from event_per_user_contribution.csv. It is useful to build importance sampling ratios and user-level DP, as it is detailed in the companion paper.