.Map :: MoHAA Mapping

Hey guys, please excuse my noobishness, but my Visdatasise has growen to an mind boggeling level, and I need to use detail brushes to bring it back down.

Can someone enlighten me to what the hell detail brushes are, and what they do. (the more detailed explination, the better) or point me to a tutorial.

Thanks

Thanks a lot man!