In some companies performance is measured based on number of emails someone sent. regardless the reason for those emails and content, what matters the most is if someone is sending something to others. So, I was asked to produce quick count how many emails one individual sent.
Here is quick PowerShell command which I ran on Exchange 2007 Mailbox server to find requested number:
get-messagetrackinglog -EventID "SUBMIT" -Sender "email@example.com" | Group Sender