I'm not sure if this is the most appropriate SE group to ask this question but I'm hopeful that it will get some interesting and helpful input from the folks here before it is possibly moved.
A friend of mine has been cyber-stalked for 4 years now by an ex-boyfriend. He recently worked out her new job email address (via LinkedIn) and started sending her emails. She told me that the emails he has constantly sent her have a similar wording and subject matter. This made me wonder if there was a way to block emails with certain word patterns or phrases for all her email accounts (Gmail, work email, etc.).