Sharing a link is also a sign up feature now. Didn't tldraw come up after Excalidraw was already quite popular? Seems like a missed opportunity for the latter since tldraw came up after and was able to figure out a business angle for a similar (same?) software.

Sorry for the logins around collaboration. I really liked the open collaboration feature too but we were getting some sketchy user behavior around it and my nerve broke. You can still join someone else’s board anonymously though. When you share a link to a board with a friend, they don’t need an account to join the board.

Excalidraw was already really established when I started tldraw, yeah. I was a contributor (the app uses my ink library perfect-freehand!) and still love the project. Excalidraw has done really well with their SaaS app Excalidraw+. I still think the bigger long term need / opportunity is for an SDK product, given that whiteboarding is becoming more of a commodity feature, like kanban boards or maps.