Okcupid - although recent dating apps are apparently more challenging, at least for a time dating sites helped nerdy people find each other, and have those awkward 'do you want to date me' conversations in a safe way.

Probably some software in a medical device that helped with some simple preventive medical procedure

Yeah whatever software they use to help discover, develop and trial vaccinations too.

Word processing software. I remember my first job as a lowly admin assistant in the Civil Service where my job was to manage with the team's post, file lots of pieces of paper, and deal with the Divisional Typing Pool ruled by the fearsome and never-to-be-forgotten Mrs Kagan. Word processors not only changed the office organisation structure forever, it saved me from having to approach Mrs Kagan to ask for a letter to be retyped because my boss wanted to add a couple of words "just here, and here - today if possible ... please?".

well I guess we have to exclude the staples, right? operating systems, infrastructure, messengers, browsers, navi apps.

I love:

org-mode

autohotkey (windows)

firefox add-ons and userscripts

an alternative keyboard layout (and QMK for a hardware implementation)

kodi

calibre

sumatra pdf

well and including historically: I learned programming through macromedia flash

Anki. Spaced repetition + testing effect made learning (math, in my case) much better and more efficient.

How did you use Anki(what kind of flashcards?) for math?

H.264 compression, or whatever makes video on the internet work.

Fast cheap bandwidth and storage too then.

Xiami, Douban, Spotify, Youtube, Bandcamp, SoundCloud, Wikipedia, RateYourMusic, Soulseek, ... no music no life!

Stand (https://getstandapp.com)

It reminds me to stand up once an hour.

git, vs code

I do most of my homework on vs code, and use git to track and archive all my coding-related stuff to private repo. Seriously, it gives me peace of mind and euphoric joy when I finish my homework and push to the repo.

Google Maps

mIRC and its "powerful" mIRC scripting. Writing bots in 1999 was more interesting than nowadays.

Vim, Intellij Idea, Java, Python, Bash

Solitaire - LOL

Internet browsers - almost any one.

GUI compilers / dev environment

GIT

Excel

Word

Emacs

Linux

Lisp

Python

I owe them pretty much everything.