On a related note, I'm curious how many here find user ratings of new movies coincide with their own. Personally, I've been sticking to critic reviews because the authors usually have a much larger base for comparison and developed tastes than the casual movie goer like me, and because user-submitted ratings like IMDb can be highly inflated as waves of unusually high ratings pour in in the first few weeks of the release ("Best romantic comedy EVR, 10/10!"). Once the dust settles, the reviews tend to sober up a bit and even out at a value that I tend to agree with more.
The other cool thing that Filmgrain captures that's different from quality is insight into what people liked about a movie afterwords. For example, people were divided on if Great Gatsby was good or not, but people couldn't stop tweeting about the soundtrack. I'd have never known how much people cared if it wasn't for this feed and it's this type of meta information we want to bring forward, as we can.
Things like RabbitMQ do this very well. You can use HA mode with RabbitMQ and not have a SPOF.
Alternatively you can use Kafka (for really big traffic) or Kestrel for the same thing - they're less sophisticated than RabbitMQ but I see that as an advantage since they're simpler.
The key to scaling and maintaining HA with redis is using clustering, either built into the app or through something like nutcracker (https://github.com/twitter/twemproxy) and making sure you properly balance.
The performance of redis makes it very worthwhile to deal with the persistence/HA issues.
When we have user accounts and other things like that, we'll have to think about how to do that the most reliable way as well, which may be Redis or may mean bringing Postgres into the mix. I think there's a lot of benefits to keeping the variety of technologies down so if we were to bring in another, it would need to offer something compelling that our current mix doesn't offer.
The major theme we were trying to highlight in this post is just how far Redis can take you if you're trying to build a component-based backend and need a way to handle the communication as well as the state of the system.