Reading Discworld!

[dehro]

I just started getting into Pratchet. I read the first book and Mort and I'd like to read more, but from what I understand there's more than one main plotline, yes?

there isn't a main plotline. each book is self-contained. But time goes on and many characters are reprised in different stages of their lives. Today's Corporal in the Night Watch will be tomorrow's Sergeant and so on... Society also evolves and a technological advancement explored and plot-relevant in one book might become background and taken for granted later on. This tends to be rather minimal and shouldn't affect reader enjoyement in a negative way (at most you won't notice a joke or two)
Reading them in publication order allows you to stay temporarily speaking on track and not miss the occasional inside-joke that might refer to staples of one or the other character that have been established in another book. That said, they're perfectly readable in whatever order... and plotwise each book really explores a separate theme (or multiples).