This post is for all the people who have been following Arbital's progress since 2015 via whispers, rumors, and clairvoyant divination. That is to say: we didn't do a very good job of communicating on our part. I hope this posts corrects some of that.
The top question on your mind is probably: "Man, I was promised that Arbital will solve X! Why hasn't it solved X already?" Where X could be intuitive explanations, online debate, all LessWrong problems, AGI, or just cancer. Well, we did try to solve the first two and it didn't work. Math explanations didn't work because we couldn't find enough people who would spend the time to write good math explanations. (That said, we did end up with some decent posts on abstract algebra. Thank you to everyone who contributed!) Debates didn't work because... well, it's a very complicated problem. There was also some disagreement within the team about the best approach, and we ended up moving too slowly.
So what now?
You are welcome to use Arbital in its current version. It's mostly stable, though a little slow sometimes. It has a few features some might find very helpful for their type of content. Eliezer is still writing AI Alignment content on it, and he heavily relies on the specific Arbital features, so it's pretty certain that the platform is not going away. In fact, if the venture fails completely, it's likely MIRI will adopt Arbital for their personal use.
I'm starting work on Arbital 2.0. It's going to be a (micro-)blogging platform. (If you are a serious blogger / Tumblr user, let me know; I'd love to ask you some questions!) I'm not trying to solve online debates, build LW 2.0, or cure cancer. It's just going to be a damn good blogging platform. If it goes well, then at some point I'd love to revisit the Arbital dream.
I'm happy to answer any and all questions in the comments.
Here is my person take on why it's complicated:
When you ask someone if they would like a debate platform and describe all the features and content it'll have, they go: "Hell yeah I'd love that!" And it took me a while to realize that what they are imagining is someone else writing all the content and doing all the heavy lifting. Then they would come along, read some of it, and may be leave a comment or two. And basically everyone is like that: they want it, but they are not willing to put in the work. And I don't blame them, because I'm not willing to put in the work (of writing) either. There are just a handful of people who are.
So the problem is definitely not on the technical side. It's a problem with the community / society in general. Except I'm hesitant to even call it a "problem," because that feels like calling gravity a "problem." This is just the way humans are. They want to do things they want to do.