[[Explain.]] Uses the AOLServer web server with embedded TCL 8.2 interpreter: Multihreaded, automatically caches interpreted code for speed. Has builtin, easy to use hooks to connect to databases like Oracle, Sybase, PostgreSQL. OpenACS is a web toolkit built on top of AOLServer. It has a strong community-oriented focus, with emphasis on bulletin boards (aka message forums), news, classifieds, as well as ecommerce functionality. It has a very strong templating system as well. Users: greenpeace.org, openacs.org, www.travelerstales.com (most functionality hidden in admin pages), www.pps.org . http://www.openacs.org