It is a Microsoft Outlook plug-in created using .Net and VSTO. This application gets embedded inside Microsoft Outlook.This application was built for a lawyer firm which wanted hourly billing for its clients when they were drafting mails, etc for their clients. FeeMail used to track total time spent while drafting any mail, it has feature of selecting by client name, case Id and so on. It also generated invoice which could be sent to client for payment, etc