It was a platform to create / edit / host frontend and node.js backend. It was popular because it was an easy and free way to deploy something on a playground.

When it went out I was super impressed, but they failed to monetize it and got badly abused by bad actors

Glitch the company also used to be Fog Creek of Joel Spolsky/FogBugz fame.

[1] https://en.wikipedia.org/wiki/Glitch,_Inc.

. (dot) got truncated

https://en.wikipedia.org/wiki/Glitch,_Inc%2E