No, I haven't...but here are a few quick thoughts off the top of my head:

- he's child # 4 of 7, the youngest with an account

- I have full access to his mailbox/account, address book, and message history

- we 'invite' him to his own events and whole-family events (so he can look forward to things, plan, etc.)

- he generally only emails his parents, siblings, extended family, and close family friends

- he knows not to enter his email address on ANY websites without me setting it up (with an email alias if appropriate)

- I have subscribed him to a few lists for kid-friendly and kid-focused news as well as some academic lists

- he needed his own email/login for certain online classes (for reminders, stats, etc.)

- his time on the (very publically-situated) family pc is limited to ~30 mins a day (M-Sa only), and supervised

- he does not have other devices, and won't until he's much older

- I have the internet connection on strict lockdown using whole-network VPN (via OpenWRT) and a combination of local and remote DNS content filters