SEASR's Tag Cloud Viewer With Stemming is a free tool for creating a tag cloud from a text hosted at a URL, and can process PDF documents. While this tool is similar to SEASR's NGram Tag Cloud Viewer, it applies a stemmer to the text during processing.
Though the page for this tool is no longer available on the SEASR website, it can still be viewed via the Internet Archive.
Comments
The website is no longer available but it can be seen from this website
https://web.archive.org/web/20121120114947/http://seasr.org/documentation/example-flows/tag-cloud-viewer