One reason: a PDF feels like a "finished publication". While HTML can be dynamically updated, a PDF is the equivalent of something "going to the press".

Another reason: for whatever reason, if you're selling your content a PDF has more intrinsic value for the end customer. It becomes "a thing" instead of just being "content that should be free". It's very odd. People like the idea of owning digital goods, but only as long as they can download them and store them on their own hard drive.

>"going to the press".

Perfect description. Word and other formats feel like a draft. By having established a legacy of making finished PDFs hard to edit without, say, a full licensed version of Acrobat, it got people into the mindset that it was the go to press format.

It's a lot easier to download and transfer a single PDF file versus downloading a complete webpage and all of its assets.

You can be sure formatting will be fine. I once bought a Kindle ebook that had lots of code samples. Even when reading on my laptop with a large screen spacing was really bad. (Though safari books online handles this well in HTML.

interesting but an issue with that is pdf dont adapt well to different screen sizes. On mobile / tablet I am yet to find anything that adjusts it to screen size without panning and zooming. Especially two column layout favoured by publications.

Because not everybody can compile my TeX documents on their machine.

In all seriousness, the only reason you should be using PDFs is if the exact presentation must be preserves. Basically, this means any documents which contain maths or figures or tables would be best constructed in TeX and turned into PDFs, so that you can control the exact presentation.

For anything else I strongly recommend people just use HTML! (Or something which can be turned into HTML.)

exact presentation definitely looks like the major reason for using pdf. I think I need to find an app that does pdf parsing similar to Pocket/ Instapaper and makes the pdf adaptable to smaller screens.

And how often are you successful at saving a webpage using Google Chrome? You cannot even say because this bozo app fails to save in a majority of cases and never once raises an error. A basic lack of fundamental core stability has driven me back in the the arms of Internet Exploder in the past 3 months. When a PDF is saved, it is saved with the entire content intact in a single repository.

A PDF comes out of any printer or press as content of it is defined (designed), this is a powerful feature, a postscript document (PDF is a glorified postscript document) is not a flowing format but a measured one and almost as accurate or as accurate as a CAD document. A PDF is intended for print, not the screen.

Pdf is very good at reproducibility at the printer.

Because HTML doesn't support content that needs to be in a paged format properly and is terrible for printing.

Companies also tend to like things as .PDFs for archiving.