Also Soundcloud, T-Mobile, yes Spotify … A lot of open source projects are based in Europe: Gitlab, Mastodon, Peertube, Mobilizon, a few Linux distributions, LibreOffice… I think at least the Free Software and libre culture world is pretty active, here.
Plus aside from consumer facing software, the tech sector also exports a lot of engineering. There is German wielded train tracks all around the world, car parts, Airbus (planes), tools, logistics software and robotics, companies like SAP do lots of behind the scenes stuff…
(And half the internet giants weren’t even founded in arbitrary places in the USA, but more or less just in California (Google, Apple, eBay, PayPal) the other half is more spread over the country, like Microsoft: New Mexico, Amazon: Washington, Facebook: Massachusetts if I’m not mistaken.)
Depends on country, if you’re a company or doing it for profit and if you do additional stuff like sending emails.
If you’re doing it for fun and are in the USA, you don’t need to do anything.
If you’re a company you should add the fine print. Add copyright notices, trademark claims, terms and conditions, disclaimers…
If you’re sending out newsletters you need to make sure people can unsubscribe.
If you’re in the EU you might need a whole imprint, privacy policy, handle user data properly…