A couple months ago I spent a weekend tossing together a webapp to do exactly this. Didn't completely finish it because I was worried about copyright.
This sounds like a great idea. And probably some who've read the sequences once would also like the chance to review and re-discuss them with a group; certainly I would.
How much programming/etc. effort and skill would it take to implement this?
I tried an RSS app that gives you a small bit of a Project Gutenberg book every day. Big problem I had with it was that I'd often want to read more than one item of the stuff, and there wasn't an easy way to both do that and keep the rss in sync.
The thing should generate a link to the next item in the sequence in each feed item, and make it so that clicking that link would drop the next item from the RSS sequence. And so on for the next item links in all the sequence items you read outside the feed reader. So you'd get item 3 in your RSS today, you'd get carried away and click onwards through items 4 to 9 outside your RSS reader and read those too, and tomorrow you'd get item 10 instead of item 4.
Archive Binge does something like that, though it looks like you do have to manually change it from 4 to 10. If we go with the individualized feed option, it's definitely a good feature, but it wouldn't work at all if we're trying to keep people reading in sync with each other.
I imagine most people would start reading at different times anyway, so things wouldn't be very synced by default. There should probably be a control panel for explicitly setting the next item for fixing a messed up read point and for ad hoc syncing of the next item.
I actually wanted to write this tool for the longest time, but then, somebody went and did it: http://rssreplay.heroku.com/
I just encountered Archive Binge, a website that makes custom RSS feeds of certain webcomics' archives, presenting a few comics per day so that people can easily catch up to those comics' current strips without overloading themselves.
I strongly suspect that a similar tool would be useful for the Sequences. It might be good to have a few extra features, like the ability to only see posts with a certain tag, but even just a basic feed that presented one or two of them a week would be useful.
It might be even more useful to, rather than allowing each person to make their own feed, have a single feed that cycles through everything and then restarts, to encourage new conversations about those articles between people who are reading the sequences at the same time. If the resulting cycle is too long, we could also have a second or third feed offset from the main one, so that no one has to wait more than a few months to subscribe to a feed that's starting at the beginning.