KFM enlarges the meaning of bookmarks. Bookmarks can refer to every file, that means apart from HTML pages and FTP directories documents, applications and *.kdelnk files. If a bookmark is selected in KFM, the convenient action follows; a document is opened, an application is started etc. To add a file to the collection of bookmarks, you only have to use the right mouse button on the file and select the entry 'Bookmarks'.
Each bookmark corresponds to a file in $HOME/.kde/share/apps/kfm/bookmarks. An entry in the bookmarks menu makes it easy to find this directory. Renaming a bookmark file also changes the bookmark menu immediately. If you open the properties for such a file, you can configure the bookmark, i.e. for example change the destination (URL) or the icon. You can move, copy and rename files in this directory tree as you desire. Please make sure that these files have a suffix *.kdelnk, so that KFM will easily distinguish them from 'normal' files.
Creating a new directory in $HOME/.kde/share/apps/kfm/bookmarks will create a submenu of the bookmark menu at the same time. To add a bookmark to the new submenu, pop it up. The first entry will add a bookmark for the current URL.
The program krootwm allows the access on the bookmarks. Clicking the right mouse botton on the background of the desktop makes (besides other stuff) the bookmark menu appear. Changings on the bookmarks are not immediately applied to krootwm yet. At the moment you have to restart krootwm to do so.