dotLRN installs on top of OpenACS 4.6.2. For convenience the dotLRN 1.0 tarball includes all the packages it needs from OpenACS 4.6.2 and configures itself on installation. You can install as many additional packages from the OpenACS 4.6.2 tarball as you want, but since they don't have portlets or applets defined for them they won't integrate smoothly. However a portlet/applet pair for (say) lars-blogger would be easy to write (hint hint)
