Ever wanted a simple, 18-page overview of General Relativity? Apparently, there’s one here. I wouldn’t know, since it’s only available in PostScript, PDF, and DVI formats, which (unless I’m being paid) I don’t download on principle.
If it’s on the web and you want people to read it, post it in fucking HTML. If it’s on the web and you want machines to read it, post it in XML. There is absolutely no reason, logic or excuse for not making a document available in one of these two formats.
By all means, provide a PDF alternative for people who want to print it out – but note the use of the word "alternative".