The fully-functional stack is over 25 programs and libraries, each requiring custom configuration, and taking days of effort. The complexity of this process has been the subject of many emails to the MapServer mailing list and others. HostGIS Linux filled its position well. In 15 minutes, you could have a freshly-installed OS with the MapServer stack and a set of a working examples using GDAL/OGR, PostGIS, OpenLayers and TileCache. This saved literally days of effort over figuring out the installation process on your own platform.