Redis is a high performance key value store database, used at places like The Guardian. Like MongoDB it also includes messaging functionality for replication, which means it’s being used for developers for all kinds of stuff, not all what it was “intended” for.
Given that just a couple of hours ago I said MongoDB is emerging from the NoSQL pack I found the chart really interesting.
Sadly our Hacker News data is not up to date (also note the x axis is incorrectly labelled. its data for 2010-2011) but I will be looking to get a better handle on Redis, and its developer mindshare with some solid data points. Watch this space.