If there are any Adroll folks on this thread, really curious to know about Adroll's use of the D programming language, how it has worked out, anecdotes, stories etc. That you use already makes it an attractive place :)
D is awesome for what we do with it. It unlocks our small team of data scientists to have a huge impact on the company, as we don't have to rely on frameworks such as your typical hadoop/spark cluster which require engineers just to maintain it. We can also use the same code path offline and online where we have very strong latency and QPS requirements.
D makes us ship more often, with less humans.
The runtime is not perfect yet, but the language and compiler are awesome. It keeps our codebase small, simple and very efficient.