Finally, Apache is used in a much flexible manner than AOLserver ever can. The modular interface with all of the different mods means that an infrastructure can be built such that Apache can interface java, php, perl etc applications. In addition, if someone builds a complex system with many redirects and virtual hosts using Apache's idiosyncratic solutions it will be a massive expensive to switch to another web app server entirely.I am not sure what you mean by Apache is used in a much flexiable manner? Apache is used and has more tools available for it, but Apache and AOLserver are to very different products there were developed with different approaches to doing this thing we call ``web server''.
Apache, itself, has not internal scripting language. By that design it HAD to be able to interface to outside languages, since that became the web markets driving force. AOLserver was built to use TCL. It never needed the ability to interface with other ``things''. One can build AOLserver modules (nsxml, nsjabber, nspam, etc.) in the same way that people build apache modules. Most people that use AOLserver don't see the NEED for them as they usually can be done ``in server''. You can't really compare the two. You use them for different purposes although the final goal is to display websites.
In terms of intergrating Apache and AOLserver in mixed enviorments, it is possible and very simple. It is not expensive or difficult to do. People mention how flexible Apache is and at the same time talk about how hard it is to us it with anything else.
If one is really wants to some merge apache and OpenACS it would be an easier task to use the xql files and databases as a base to build a php/java/python/etc application around it. In both cases (mod_aolserver or a complete different language) you'll be spending quite a bit of time keeping code in sync.
