This paper describes a set of visualization tools which aid the understanding of discussion topics and trends in online discussion forums. The tools integrate into the forum's web page, allowing for easy exploration of its contents. Three visualizations are presented: a visual browsing suggestions mechanism, a semantic "atlas" providing a thematic overview of larger forum segments, and a timeline displaying temporal evolution of forum topics. The underlying algorithms have very few language-dependent components. The software is operational and can be tested live on Slovene, Slovak and Hungarian pilot sites, containing up to 5 million forum posts.