Great! You're just in time! (Well, there's kind of never a bad time for a web developer...!)
What is the top priority at the moment?
Your work and insights on a homepage are still of course important. But right now where we need the most help is in getting auditing and assistance from someone who does web for a living and can look at how we can make the most turnkey experience and best practices for providing an interpreter that people can use in their own pages.
As an example of the kind of demos we are envisioning: @rgchris is aiming to use the embedded interpreter to do a kind of "live rendering" of his StyleTalk dialect to CSS, which would make a nice demo. He suggests this "CommonMark Dingus" as a model.
And the web tutorial itself will ideally be a demo of the capabilities as we sort of scrape through it. If you give a read to On Giving libRebol.js More Power than JavaScript you can see a phrasing of a challenge that has now been shown in proof-of-concept...we can actually use wasm threading to accomplish just that. This is an interesting situation of Rebol being ahead of the curve with technologies that will be relevant tomorrow, instead of yesterday. 
How can I help?
By doing what interests you, that keeps you interested! There's always going to be more value in being present and giving day to day feedback, than in being bored and going missing... 
But, auditing the replpad.js project for any low-hanging fruit of things you see that could be done better would be a helpful start. The goal is to be very thin on use of frameworks (it does not use jQuery) because I'd like the console to be something you could factor out--and perhaps even load dynamically. So you could even perhaps have a page deployed that used a thin libr3.js that requested and fetched the console extension and opened it in a window on demand.
But that's the console...which shouldn't be conflated with the tutorial...though the tutorial should use the console. It's all a factoring work-in-progress and a lot to think about.
So it's a delicate balance of trying to stay minimal, with still wanting to be blended in with whatever the mondo Angular or React, or whatever people want to use is. Counsel on all these matters would be of most immediate use (vs. the homepage, which we'll need too...so don't lose it!)