ElkArte is described as 'modern, powerful community building forum software. It is completely free to use and is licensed with an open source BSD-3 clause license' and is an app in the Social & Communications category. There are five alternatives to ElkArte for a variety of platforms, including Self-Hosted solutions, Mac, Windows, Linux and Online / Web-based. The best alternative is phpBB, which is both free and Open Source. Other great apps like ElkArte are MyBB (Free, Open Source), Flatboard (Free, Open Source), Vanilla (Free Personal, Open Source) and Foru.ms (Free).
Since its creation in 2000, phpBB™ has become the most widely used Open Source forum solution. Like its predecessors, phpBB™ 3.2 “Rhea” has an easy to use administration panel and a user friendly installation process, which allows you to have a forum set up in minutes.