Rockdove is the backend service that powers the geospatial features on Twitter.com and the Twitter API ("Twitter Places"). It provides a datastore for places and a geospatial search engine to find them. To throw out some buzzwords, it is:
Rockdove is written entirely in Scala and was developed by 2 engineers with no prior Scala experience (nor with Java or the JVM). We think the geospatial search engine provides an interesting case study as it presents a mix of algorithm problems and "classic" scaling and optimization issues. We will report on our experience using Scala, focusing especially on: