Measurement Window
Blubrry uses a fixed 24-hour measurement window, in addition to an hourly breakdown at the episode level and month aggregations at all levels.
Measuring Uniques
Blubrry uses a proprietary method that counts no more than two downloads from any IP on each media URL per day.
From comparative analysis we know that this method is comparable to the more common IP + user agent method, with additional protection against fraud by user agent spoofing.
IP Hashing
Blubrry hashes the last octect of IPV4 addresses before saving them to the database. Hashed IPs get deleted from the database in three months.
Blubrry does not currently support IPV6.
Exclusion List
Blubrry ingests Udger’s datacenter list using their Local Parser subscription.
For any data centers found to be missing from the Udger list, Blubrry queries hackertarget’s https://hackertarget.com/as-ip-lookup/.
These lists are re-ingested on the second day of the month and used to update Blubrry’s exclusion list. The system is audited quarterly to find new data centers and other anomalies.