We had a meetup on RSSCloud (organized by Nick) at the School of Information today. In a nutshell, RSSCloud is an effort to make the web real time. It has been in the news lately after Wordpress added support for it. Dave Winer went through the details and Matt Mullenweg and team described their experience implementing it in Wordpress. Unfortunately, I had to miss part of the meetup to attend a talk by Vinod Khosla, which was excellent. I’m sure I missed some interesting discussion around RSSCloud and PubSubHubbub (PuSH). I don’t see the end user losing in the contest for adoption. Both are open protocols and will only make the web better. Many services may just add support for both. Given how open Automattic / Wordpress is, it wasn’t surprising to hear that there are plans for PuSH support at some point in the future. RSSCloud got there first because it was easier to implement.

I’ve wondered how hubs, in both protocols, handle updates when there are lots of subscribers (in the millions). The obvious answer is a job queue, and that’s what one of the PuSH implementations of the hub does (backed by RabbitMQ). I asked Joseph Scott, the Wordpress developer who implemented the feature what they do for WP.com, and I believe it’s something similar. The Wordpress plugin at this point just sequentially pings all subscribers. That should be sufficient for the vast majority of users. The interesting problem is how real time it would be when a hub has to update 10 million subscribers? Also, what is acceptable as real time? 1 second, 10 seconds, 1 minute? Interesting thought experiment, but I think that’s a problem to be solved when we get to it.

The best part of the day was that I finally met Doug Kaye in person at the meetup. He’s the father of podcasting if you’re not aware.