[jumpkick]

Have a reasonable retention policy on these backups. Backups are a "legitimate business interest" and you don't need to purge "right to be forgotten" requests from your backups if you stick to a reasonable and publicly-documented retention policy. This is advice that I've received from counsel. However, I am not a lawyer, and this in no way should be taken as legal advice.

[cobbzilla]

If you ever had to restore from backup, I hope you kept track of what content now needs to be "re-forgotten"

[leesalminen]

We received similar advice from our legal counsel, but got stuck on this implementation detail.