Work yet to be done

More advanced tutorial-style documentation
An example that spiders a Haddock package's docs to validate its internal and external links
Integration with tagsoup (see the mess in UploadPaste.hs)
International domain support?
Better authentication support, including session-long memory of which URLs do and don't need authentication
Some poor sod needs to add digest authentication to http-client so we can use it
Cache management