I have just installed kde4.1.2 following the procedure in http://pkg-kde.alioth.debian.org/experimental.html
At some point in the installation, all my ~.kde/share/apps/ files got deleted and were not replaced. This of course means all mail, bookmarks, etc. could get trashed during this install. It also means that all applications have to be set up from scratch again. I had backups...but ..... Please add a warning on the "how-to" page that this may happen. Not everybody keeps a backup of ~.kde/ Thanks -- http://lists.alioth.debian.org/mailman/listinfo/pkg-kde-talk
