[exhilaration]

I bet it's Usenet users. WinRAR can split large files into chunks that are uploaded as separate Usenet messages.

[JackeJR]

And also have parity built in for file recovery. The alternative will be to use par2 to create parity files.

[qingcharles]

The parity files are the killer feature for me. Probably 95% of the downloads from Usenet end up needing them.

[dmonitor]

7z also does this now FWIW

I'd still bet it's Usenet users that installed WinRAR way back when and have stuck to it ever since

[kayson]

That's me. But now everything is done automagically by nzbget and I use nanazip on my Windows desktop.