A very basic tool to keep track of your domain names and servers.
Picture the scene: you own and/or manage multiple domain names, purchased from a number of different registrars. You use a few different DNS and web hosting providers and have multiple servers dotted around the globe. Keeping track of all that is a pain. If a server, or any other link in the above chain goes down, how can you quickly find what is hosted where? How many of your clients are affected? You can create a complex spreadsheet and employ various filters to do all that for you, but this is hopefully a little less painful.