We're working on expanding the official counters docs. We'll also have a blog post up about it next week.
Basho Hacker Sam Elliott started a CRDT cookbook that will walk you through using the counters in 1.4 (and eventually the new data types we add). That should get you started.
https://github.com/lenary/riak_crdt_cookbook/tree/counter_ex...
Enjoy. Also, come to ricon.io/west.html. We'll be talking plenty about Counters and all the huge stuff coming to Riak in the near future...