Updating written guidelines regularly is difficult and expensive. New evidence in cancer treatment is published frequently. Guideline booklets are also difficult to disseminate widely and stakeholder feedback is mainly pre-publication. To address these issues, Cancer Council Australia developed a web-based wiki platform for guidelines. Only invited expert authors can write in the wiki guidelines, but any stakeholder can comment upon them at any time. The key steps in guideline development were integrated with the wiki capability. An expert group, whose competing interests are documented, were identified, the key clinical questions and search strategies were developed for each question and literature searches recorded on the wiki. An online literature screening and critical appraisal process was developed. Evidence-based recommendations were formulated and evidence tables automatically generated. The stakeholders were invited to comment online. Web analytics monitored usage. The writers remain engaged to appraise new papers and update the guideline rapidly as necessary. All previous versions could be accessed. We evaluated lung cancer treatment guidelines developed on the wiki, where 22 authors identified 67 clinical questions. The literature search and screening process resulted in 2035 potentially relevant articles being forwarded for detailed methodological evaluation with another 571 added through snowballing and other methods. To fine-tune the initial draft content, the working party used the wiki to exchange 156 internal comments in 9 weeks. Of 1055 visits in a 30 day initial consultation period 487 were targeted by email and 387 found the site by Google searches. Of respondents from 45 countries, most were from Australia (799 visits), New Zealand (60 visits) and the United States (31 visits) Of 38 comments, 31 resulted in edits. A strategy to boost uptake is to write Qstream education modules to accompany the guidelines.