1. A REPL-first environment. We believe when hackers start coding they generally start sketching things out and a fast iteration loop makes it easy to make progress. That's why Repl.it starts out as a REPL. This also makes it less intimidating and more useful for newbies. Everyone's first program is a text-based program as GUI is really hard to get started with.
2. We're building a generic toolchain that could be decomposed and used in different ways. We built a highly dynamic IDE[0], and a super fast container orchestration system that works as both a development environment and a hosting platform[1]. We're starting to explore what that means by building plugins to other editors and making it available on the cli[2].
3. Repl.it's has an awesome community of hackers collaborating, helping, and building stuff for each other. We have a Hackernews-like forum where people can share their creations, ask questions, or teach others and, it's creating an awesome positive-feedback loop in the community[3].
[1]: https://repl.it/blog/deploy
[2]: https://github.com/replit/repl.sh
[3]: https://repl.it/talk