The URLs ended in .html because that's how the files in the file system were named. Note that logging is best done as a trace filter. You don't want the act of logging to slow down the user experience. The most prominent difference between AOLservers 2.3 and 3.0 is the nontechnical one of operating licenses. In contrast, the AOLserver Public License governs 3.0.
Some organizations require open source.
Others forbid its use. Those willing to consider both can compare AOLserver versions in a few technical dimensions. AOLserver 2.3 has matured for more than two years. Version 3.0 is officially a beta release. Some vendors use beta as a euphemism for flaky or untested.