Number of exploited users: Email data

We’ve completed sending out notifications to all affected users of Friday’s exploit. Email notifications started going out at 19:31 on the 25th of January at a rate of 1 per second and finished at 18:32 on the 26th of January.

There were 81,205 email addresses included in the exploited data – of those, 598 were exact duplicates. We therefore tried sending to 79,809 different addresses (we didn’t filter the list any further at this point as we just wanted people to be notified as quickly as possible).

After the emails were sent, we did analyse the data and found:
* 12 email addresses did not actually have a valid domain name structure
* 2,906 email addresses were sent to domains which cannot receive email (such as no longer being registered)
* 14,427 email addresses were actually duplicates (such as and, and and and
* 31,582 email addresses were on “common domains” (defined as,,,,,,,,,,,,,,,, and
* 19,467 email addresses were classed as “likely spammers” (the domain was listed on but wasn’t in the list of “common domains”)
* 5,029 “other” email addresses looked valid, had good DNS entries and were not listed on the common domains and “likely spammers” list
* 12 of those email accounts accounts were over quota and have not yet received the notification.

We are therefore counting the number of exposed “data users” as “common domains”+”others”:-“over quota”: 35,599.

The top 20 most common domain names used (and their classifications) were:
1. (31,159 emails) [Common domain]
2. (5,605 emails) [Spammer domain]
3. (5,491 emails) [Common domain]
4. (2,893 emails) [Common domain]
5. (1,792 emails) [Common domain]
6. (1,288 emails) [Invalid domain]
7. (1,159 emails) [Spammer domain]
8. (1,095 emails) [Spammer domain]
9. (1,056 emails) [Common domain]
10. (1,016 emails) [Common domain]
11. (913 emails) [Spammer domain]
12. (842 emails) [Spammer domain]
13. (672 emails) [Spammer domain]
14. (645 emails) [Spammer domain]
15. (596 emails) [Spammer domain]
16. (594 emails) [Spammer domain]
17. (576 emails) [Invalid domain]
18. (496 emails) [Spammer domain]
19. (424 emails) [Spammer domain]
20. (414 emails) [Spammer domain]