Lean knowledge management is today implemented mostly through wikis, which let users enter text and other data, such as files, and connect the content through hyperlinks. Easy setup and a huge variety of editing support are primary reasons for wiki use in all types of intranet- and Internet-based information sharing (see P. Louridas, "Using Wikis in Software Development," IEEE Software, Mar. 2006, pp. 88- 91). The drawbacks show up when you need to structure data as opposed to just edit text. Many wikis have tons of useful content, but the volume and lack of structure make it inaccessible over time. This is where semantic wikis enter the picture. Sebastian Schaffert and his colleagues describe them here and explain how to model wiki knowledge and content for improved usability. I look forward to hearing from both readers and prospective authors about this column and the technologies you want to know more about.