@OakIris - I don't have a Kindle (I use the PRS-900) and I'm not the original poster, but what I can say is that in my experience, djvu's are used primarily in the world of math articles/books (and science, I believe. I don't actually read these, but I've been told they commonly use the djvu format). A main reason for this is that there is currently no way to reliably simply making mathematical expressions in any of the normal ebook or document formats--ie epub, rtf, etc--so one is left with exporting to some sort of portable document format--such as djvu, ps, or pdf.
Of those formats djvu tends to use less resources (as is mentioned above) and generally look smoother (it doesn't have any loading time in panning or zooming, it doesn't need to re-render things, etc.). I myself tend to prefer pdfs because there are many more viewing options for them, but unfortunately I am unable to force all the other mathematicians of the world to convert to my point of view. This means that I regularly view djvu documents, both on my computer (when it's a short article or I'm just looking up a particular fact) and on my prs-900.
@alexibm I don't if this is good enough for your purposes or not, but one option is always opening your djvu in
DJView and then just telling DJView to "export as" pdf. The downside of this is that you basically end up with a pdf of the pages as images, so your text will become unsearchable and your file size will become much bigger. Since most of the older articles I find are really just scans (You mean journals
don't keep digital files of all their articles for the next 40 years?!), the first issue not always a big problem but the later is certainly annoying.
Another option that I've used for viewing djvu on my reader is
pdflrf. I know that the Kindle does not read lrf files, but Calibre can easily convert lrf's to viewable files on the Kindle. The reason why I'm suggesting this tool is that it is particularly nice for optimizing djvu files for reading landscape on smaller screens (you can set the particular width and height of the Kindle), and in streamlining the file for the ereader. It tends to result in slightly smaller file sizes than just converting directly to pdf via djview, and in darker text which can be nice if you have a file with lots of automata diagrams, etc.--the downside is that the very optimization for landscape viewing breaks up any given page into about three pages on the ereader which no longer allows you to quickly page to a particular page that might referenced in an index.
Hope that helps!