How to do newlines on the stackoverflow website?
Say I want to make two newlines between my paragraphs - is that possible to do without using
<br/>, which as I've read here is not encouraged?
It's not encouraged because it creates excess vertical white-space, which spreads out the post across the screen and allows less content to appear on the page overall. There's really no reason where you'd need to do this, and I guarantee you someone would edit the extra line-break out. Just start a new paragraph if you need some spacing between two lines of text.
In the specific case you linked too, however, the newline is discouraged because it's not the proper way to format that kind of data (columns from an Excel spreadsheet) in a post.