Most redis-based queues/websocket servers makes use of Redis Pub/Sub. StackOverflow uses Redis Pub/Sub for maintaining synchronized local caches in their load balanced web servers. Whilst StackOverflow Careers uses a Pub/Sub powered RedisMQ host for its BackOffice services: https://github.com/ServiceStack/ServiceStack/wiki/Messaging-...

@antirez has written about Redis's Pub/Sub impressive performance: https://groups.google.com/d/msg/redis-db/R09u__3Jzfk/4hPvMJY...