If you enable automatic updates to Windows, it’ll appear on your machine in the next couple of days (or may already be there; mine installed itself this morning). If you do manual updates, keep an eye out for it. In theory, you can mark it not to be installed, it ought not to and should stop nagging you (though since Microsoft admit they install updates even when the feature is turned off, I’d not trust this.)
But what if it has already installed? Can you get rid of it? Well give it a try first, you might like it. If you don’t there are various ways of disabling it, but I’ve no idea how to uninstall it. It installs itself as a service, so can be disabled that way apparently (I’ve not tried this though). Alternatively, simply follow Scott Hanselman’s advice by running up regedit, select the HKEY_CURRENT_USER\Software\Microsoft\Windows Desktop Search\DS key and then set “ShowStartSearchBand” to 0. Finally remove “Windows Desktop Search” from the startup folder in your start menu and it should plague you no more.
I have added a new post describing various ways of removing WDS if you are not content with just disabling it