Abstract Tagging has become a primary tool for users to organize and share digital content on many social media sites. In addition, tag information has been shown to enhance capabilities of existing search engines. However, many resources on the web still lack tag information. This paper proposes a content-based approach to tag recommendation which can be applied to webpages with or without prior tag information. While social bookmarking service such as Delicious1 enables users to share annotated bookmarks, tag recommendation is available only for pages with tags specifified by other users. Our proposed approach is motivated by the observation that similar webpages tend to have the same tags. Each webpage can therefore share the tags they own with similar webpages. The propagation of a tag depends on its weight in the originating webpage and the similarity between the sending and receiving webpages. The similarity metric between two webpages is defifined as a linear combination of four cosine similarities, taking into account both tag information and page content. Experiments using data crawled from Delicious show that the proposed method is effective in populating untagged webpages with the correct tags