Spotless disables the content indexing of volumes. This prevents indexes from being created. This does not prevent Spotlight from finding files by name. When content indexing is turned off, Spotlight will still find files on that volume exactly the same way the "find" function in Mac OS X 10.0.x through 10.3.x used to. If you really do not want to be able to find your files - even by name, then the volume should be added to the Spotlight privacy list.

In order to add a volume to the privacy list, content indexing MUST be enabled for that volume.

Spotless allows users to quickly disable content indexing on volumes that need to maintain a high data transfer rate for tasks - such as video rendering, Photoshop scratch disks, etc. Content indexing on volumes like these causes frame skipping, slow rendering, spinning beach balls (esp. in Photoshop), etc. The change stays with the volume - even if it is moved to another computer.