S4: Distributed stream computing platform from Apache

S4 was retired (closed) in 2014: https://incubator.apache.org/projects/s4.html

Also, bad name: http://www.supersimplestorageservice.com/

Is there a guide that lists all the Apache projects and examples of when to use them?

Shameless self promotion, Pachyderm is a slightly different approach to this problem.

https://github.com/pachyderm/pachyderm

It's look like dead, especially taking into account the other projects like Flink, Spark, etc. that are alive...

first time I hear about it! Crazy how many tools try to solve this kind of problem nowadays :O

Am I right in saying this project hasn't been updated since 2013?

Maybe what you're actually looking for is Apache Kafka?