If you’re a researcher type or just want to inform yourself deeply on a particular topic, DocJax could be your thing. Of course, you could use Google to search by file type, and even preview some files as HTML, but as Lifehacker reports today, DocJax is built for just documents. The search is fast, and the results are displayed well with document types being marked clearly by large, easy to understand icons (DocJax returns results for PDF, XLS, DOC and PPT). From your first search, you can narrow by file type using the links in the upper-right corner of the results.
In theory DocJax offers a more robust preview of everything it finds than Google – by using the Scribd iPaper tool to convert a document after you’ve clicked on ‘preview’. I didn’t have much luck though with that conversion: it only worked once out of six links I tried. Originally I thought that I might need password access to the different documents I had chosen, but I had no problems downloading them. So while the iPaper tool as a reader might conceptually offer better viewing results and options than a Google’s HTML conversion, I’ve got the feeling there’s room for improvement.