Thanks! Good documentation is a critical part of having a usable project, and that will always be a focus of Storm. If you have any feedback for how the documentation can be better, please let me know.
Just to point out, Nathan will be speaking at the Clojure/Conj conference this year. Talking about Cascalog.
I have a schedule conflict this year :( but would recommend the conference to everyone - the first year was informative with contagious enthusiasm. The other speakers also look cool.
The biggest difference is that Storm guarantees that data will be processed, whereas S4 can lose data. I also think Storm is significantly easier to use.
I've written a lot of documentation on the wiki, which you can find here: https://github.com/nathanmarz/storm/wiki
There's a few companion projects to Storm. These are:
One-click deploy for Storm on EC2: https://github.com/nathanmarz/storm-deploy
Adapter to use Kestrel as a Spout within Storm: https://github.com/nathanmarz/storm-kestrel
Starter project with example topologies that you can run in local mode: https://github.com/nathanmarz/storm-starter
Feel free to ask me questions here or on Storm's mailing list ( http://groups.google.com/group/storm-user ), and I'll answer as best I can!