A basic, step-by-step introduction by Olexiy Prokhorenko for setting up HBase and start using it to build a forum-like solution using Ruby. In case you are interesting on how to build a message board system or play with something similar to Stackoverflow in MongoDB, make sure you check the MongoDB usecases.
The post contains details about the available HBase Ruby libraries:
and the documentation that got him started:
I’d definitely add to these: HBase vs BigTable Comparison and ☞ HBase Architecture 101 - Storage.
The article contains tons of code snippets and details (nb sometimes a bit too much though) on how to get up and running with HBase and Ruby.