Tocomail is an interesting app geared towards the parents of kids that have access to email. The app sports a kid-friendly interface, personalized email addresses, and more premium features that help manage who and what their kids interact with electronically.
Now the app has added another feature: the ability to apply a bullying recognition filter to incoming emails. The filter looks for key words and contextual phrases, and when email messages containing such are found they are quarantined for further attention from parents/responsible adults, at which point it can be released to the child or disposed of.
Tocomail is available in a free iteration on the App Store; the aforementioned premium features are available for $2.99/month or $29.99/year via in-app purchase.